Bump requests from 2.31.0 to 2.32.0 in /drivers/gpu/drm/ci/xfails #8

dependabot · 2024-05-21T06:46:35Z

Bumps requests from 2.31.0 to 2.32.0.

Release notes

v2.32.0

2.32.0 (2024-05-20)

🐍 PYCON US 2024 EDITION 🐍

Security

Fixed an issue where setting verify=False on the first request from a Session will cause subsequent requests to the same origin to also ignore cert verification, regardless of the value of verify. (GHSA-9wx4-h78v-vm56)

Improvements

verify=True now reuses a global SSLContext which should improve request time variance between first and subsequent requests. It should also minimize certificate load time on Windows systems when using a Python version built with OpenSSL 3.x. (#6667)

Requests now supports optional use of character detection (chardet or charset_normalizer) when repackaged or vendored. This enables pip and other projects to minimize their vendoring surface area. The Response.text() and apparent_encoding APIs will default to utf-8 if neither library is present. (#6702)

Bugfixes

Fixed bug in length detection where emoji length was incorrectly calculated in the request content-length. (#6589)

Fixed deserialization bug in JSONDecodeError. (#6629)

Fixed bug where an extra leading / (path separator) could lead urllib3 to unnecessarily reparse the request URI. (#6644)

Deprecations

Requests has officially added support for CPython 3.12 (#6503)

Requests has officially added support for PyPy 3.9 and 3.10 (#6641)

Requests has officially dropped support for CPython 3.7 (#6642)

Requests has officially dropped support for PyPy 3.7 and 3.8 (#6641)

Documentation

Various typo fixes and doc improvements.

Packaging

Requests has started adopting some modern packaging practices. The source files for the projects (formerly requests) is now located in src/requests in the Requests sdist. (#6506)

Starting in Requests 2.33.0, Requests will migrate to a PEP 517 build system using hatchling. This should not impact the average user, but extremely old versions of packaging utilities may have issues with the new packaging format.

New Contributors

@matthewarmand made their first contribution in psf/requests#6258

@cpzt made their first contribution in psf/requests#6456

... (truncated)

Changelog

Sourced from requests's changelog.

2.32.0 (2024-05-20)

Security

Fixed an issue where setting verify=False on the first request from a Session will cause subsequent requests to the same origin to also ignore cert verification, regardless of the value of verify. (GHSA-9wx4-h78v-vm56)

Improvements

verify=True now reuses a global SSLContext which should improve request time variance between first and subsequent requests. It should also minimize certificate load time on Windows systems when using a Python version built with OpenSSL 3.x. (#6667)

Requests now supports optional use of character detection (chardet or charset_normalizer) when repackaged or vendored. This enables pip and other projects to minimize their vendoring surface area. The Response.text() and apparent_encoding APIs will default to utf-8 if neither library is present. (#6702)

Bugfixes

Fixed bug in length detection where emoji length was incorrectly calculated in the request content-length. (#6589)

Fixed deserialization bug in JSONDecodeError. (#6629)

Fixed bug where an extra leading / (path separator) could lead urllib3 to unnecessarily reparse the request URI. (#6644)

Deprecations

Requests has officially added support for CPython 3.12 (#6503)

Requests has officially added support for PyPy 3.9 and 3.10 (#6641)

Requests has officially dropped support for CPython 3.7 (#6642)

Requests has officially dropped support for PyPy 3.7 and 3.8 (#6641)

Documentation

Various typo fixes and doc improvements.

Packaging

Requests has started adopting some modern packaging practices. The source files for the projects (formerly requests) is now located in src/requests in the Requests sdist. (#6506)

Starting in Requests 2.33.0, Requests will migrate to a PEP 517 build system using hatchling. This should not impact the average user, but extremely old versions of packaging utilities may have issues with the new packaging format.

Commits

d6ebc4a v2.32.0
9a40d12 Avoid reloading root certificates to improve concurrent performance (#6667)
0c030f7 Merge pull request #6702 from nateprewitt/no_char_detection
555b870 Allow character detection dependencies to be optional in post-packaging steps
d6dded3 Merge pull request #6700 from franekmagiera/update-redirect-to-invalid-uri-test
bf24b7d Use an invalid URI that will not cause httpbin to throw 500
2d5f547 Pin 3.8 and 3.9 runners back to macos-13 (#6688)
f1bb07d Merge pull request #6687 from psf/dependabot/github_actions/github/codeql-act...
60047ad Bump github/codeql-action from 3.24.0 to 3.25.0
31ebb81 Merge pull request #6682 from frenzymadness/pytest8
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--- updated-dependencies: - dependency-name: requests dependency-type: direct:production ... Signed-off-by: dependabot[bot] <support@github.com>

dependabot · 2024-05-21T07:52:18Z

OK, I won't notify you again about this release, but will get in touch when a new version is available. If you'd rather skip all updates until the next major or minor version, let me know by commenting @dependabot ignore this major version or @dependabot ignore this minor version.

If you change your mind, just re-open this PR and I'll resolve any conflicts on it.

When CONFIG_DEBUG_BUGVERBOSE=n, we fail to add necessary padding bytes to bug_table entries, and as a result the last entry in a bug table will be ignored, potentially leading to an unexpected panic(). All prior entries in the table will be handled correctly. The arm64 ABI requires that struct fields of up to 8 bytes are naturally-aligned, with padding added within a struct such that struct are suitably aligned within arrays. When CONFIG_DEBUG_BUGVERPOSE=y, the layout of a bug_entry is: struct bug_entry { signed int bug_addr_disp; // 4 bytes signed int file_disp; // 4 bytes unsigned short line; // 2 bytes unsigned short flags; // 2 bytes } ... with 12 bytes total, requiring 4-byte alignment. When CONFIG_DEBUG_BUGVERBOSE=n, the layout of a bug_entry is: struct bug_entry { signed int bug_addr_disp; // 4 bytes unsigned short flags; // 2 bytes < implicit padding > // 2 bytes } ... with 8 bytes total, with 6 bytes of data and 2 bytes of trailing padding, requiring 4-byte alginment. When we create a bug_entry in assembly, we align the start of the entry to 4 bytes, which implicitly handles padding for any prior entries. However, we do not align the end of the entry, and so when CONFIG_DEBUG_BUGVERBOSE=n, the final entry lacks the trailing padding bytes. For the main kernel image this is not a problem as find_bug() doesn't depend on the trailing padding bytes when searching for entries: for (bug = __start___bug_table; bug < __stop___bug_table; ++bug) if (bugaddr == bug_addr(bug)) return bug; However for modules, module_bug_finalize() depends on the trailing bytes when calculating the number of entries: mod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry); ... and as the last bug_entry lacks the necessary padding bytes, this entry will not be counted, e.g. in the case of a single entry: sechdrs[i].sh_size == 6 sizeof(struct bug_entry) == 8; sechdrs[i].sh_size / sizeof(struct bug_entry) == 0; Consequently module_find_bug() will miss the last bug_entry when it does: for (i = 0; i < mod->num_bugs; ++i, ++bug) if (bugaddr == bug_addr(bug)) goto out; ... which can lead to a kenrel panic due to an unhandled bug. This can be demonstrated with the following module: static int __init buginit(void) { WARN(1, "hello\n"); return 0; } static void __exit bugexit(void) { } module_init(buginit); module_exit(bugexit); MODULE_LICENSE("GPL"); ... which will trigger a kernel panic when loaded: ------------[ cut here ]------------ hello Unexpected kernel BRK exception at EL1 Internal error: BRK handler: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: hello(O+) CPU: 0 PID: 50 Comm: insmod Tainted: G O 6.9.1 #8 Hardware name: linux,dummy-virt (DT) pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : buginit+0x18/0x1000 [hello] lr : buginit+0x18/0x1000 [hello] sp : ffff800080533ae0 x29: ffff800080533ae0 x28: 0000000000000000 x27: 0000000000000000 x26: ffffaba8c4e70510 x25: ffff800080533c30 x24: ffffaba8c4a28a58 x23: 0000000000000000 x22: 0000000000000000 x21: ffff3947c0eab3c0 x20: ffffaba8c4e3f000 x19: ffffaba846464000 x18: 0000000000000006 x17: 0000000000000000 x16: ffffaba8c2492834 x15: 0720072007200720 x14: 0720072007200720 x13: ffffaba8c49b27c8 x12: 0000000000000312 x11: 0000000000000106 x10: ffffaba8c4a0a7c8 x9 : ffffaba8c49b27c8 x8 : 00000000ffffefff x7 : ffffaba8c4a0a7c8 x6 : 80000000fffff000 x5 : 0000000000000107 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff3947c0eab3c0 Call trace: buginit+0x18/0x1000 [hello] do_one_initcall+0x80/0x1c8 do_init_module+0x60/0x218 load_module+0x1ba4/0x1d70 __do_sys_init_module+0x198/0x1d0 __arm64_sys_init_module+0x1c/0x28 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0x40/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x34/0xd8 el0t_64_sync_handler+0x120/0x12c el0t_64_sync+0x190/0x194 Code: d0ffffe0 910003fd 91000000 9400000b (d4210000) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: BRK handler: Fatal exception Fix this by always aligning the end of a bug_entry to 4 bytes, which is correct regardless of CONFIG_DEBUG_BUGVERBOSE. Fixes: 9fb7410 ("arm64/BUG: Use BRK instruction for generic BUG traps") Signed-off-by: Yuanbin Xie <xieyuanbin1@huawei.com> Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/1716212077-43826-1-git-send-email-xiaojiangfeng@huawei.com Signed-off-by: Will Deacon <will@kernel.org>

The session has a header in it which contains a perf env with bpf_progs. The bpf_progs are accessed by the sideband thread and so the sideband thread must be stopped before the session is deleted, to avoid a use after free. This error was detected by AddressSanitizer in the following: ==2054673==ERROR: AddressSanitizer: heap-use-after-free on address 0x61d000161e00 at pc 0x55769289de54 bp 0x7f9df36d4ab0 sp 0x7f9df36d4aa8 READ of size 8 at 0x61d000161e00 thread T1 #0 0x55769289de53 in __perf_env__insert_bpf_prog_info util/env.c:42 #1 0x55769289dbb1 in perf_env__insert_bpf_prog_info util/env.c:29 #2 0x557692bbae29 in perf_env__add_bpf_info util/bpf-event.c:483 #3 0x557692bbb01a in bpf_event__sb_cb util/bpf-event.c:512 #4 0x5576928b75f4 in perf_evlist__poll_thread util/sideband_evlist.c:68 #5 0x7f9df96a63eb in start_thread nptl/pthread_create.c:444 #6 0x7f9df9726a4b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 0x61d000161e00 is located 384 bytes inside of 2136-byte region [0x61d000161c80,0x61d0001624d8) freed by thread T0 here: #0 0x7f9dfa6d7288 in __interceptor_free libsanitizer/asan/asan_malloc_linux.cpp:52 #1 0x557692978d50 in perf_session__delete util/session.c:319 #2 0x557692673959 in __cmd_record tools/perf/builtin-record.c:2884 #3 0x55769267a9f0 in cmd_record tools/perf/builtin-record.c:4259 #4 0x55769286710c in run_builtin tools/perf/perf.c:349 #5 0x557692867678 in handle_internal_command tools/perf/perf.c:402 #6 0x557692867a40 in run_argv tools/perf/perf.c:446 #7 0x557692867fae in main tools/perf/perf.c:562 #8 0x7f9df96456c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 Fixes: 657ee55 ("perf evlist: Introduce side band thread") Signed-off-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Disha Goel <disgoel@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Yicong Yang <yangyicong@hisilicon.com> Link: https://lore.kernel.org/r/20240301074639.2260708-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

ui_browser__show() is capturing the input title that is stack allocated memory in hist_browser__run(). Avoid a use after return by strdup-ing the string. Committer notes: Further explanation from Ian Rogers: My command line using tui is: $ sudo bash -c 'rm /tmp/asan.log*; export ASAN_OPTIONS="log_path=/tmp/asan.log"; /tmp/perf/perf mem record -a sleep 1; /tmp/perf/perf mem report' I then go to the perf annotate view and quit. This triggers the asan error (from the log file): ``` ==1254591==ERROR: AddressSanitizer: stack-use-after-return on address 0x7f2813331920 at pc 0x7f28180 65991 bp 0x7fff0a21c750 sp 0x7fff0a21bf10 READ of size 80 at 0x7f2813331920 thread T0 #0 0x7f2818065990 in __interceptor_strlen ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:461 #1 0x7f2817698251 in SLsmg_write_wrapped_string (/lib/x86_64-linux-gnu/libslang.so.2+0x98251) #2 0x7f28176984b9 in SLsmg_write_nstring (/lib/x86_64-linux-gnu/libslang.so.2+0x984b9) #3 0x55c94045b365 in ui_browser__write_nstring ui/browser.c:60 #4 0x55c94045c558 in __ui_browser__show_title ui/browser.c:266 #5 0x55c94045c776 in ui_browser__show ui/browser.c:288 #6 0x55c94045c06d in ui_browser__handle_resize ui/browser.c:206 #7 0x55c94047979b in do_annotate ui/browsers/hists.c:2458 #8 0x55c94047fb17 in evsel__hists_browse ui/browsers/hists.c:3412 #9 0x55c940480a0c in perf_evsel_menu__run ui/browsers/hists.c:3527 #10 0x55c940481108 in __evlist__tui_browse_hists ui/browsers/hists.c:3613 #11 0x55c9404813f7 in evlist__tui_browse_hists ui/browsers/hists.c:3661 #12 0x55c93ffa253f in report__browse_hists tools/perf/builtin-report.c:671 #13 0x55c93ffa58ca in __cmd_report tools/perf/builtin-report.c:1141 #14 0x55c93ffaf159 in cmd_report tools/perf/builtin-report.c:1805 #15 0x55c94000c05c in report_events tools/perf/builtin-mem.c:374 #16 0x55c94000d96d in cmd_mem tools/perf/builtin-mem.c:516 #17 0x55c9400e44ee in run_builtin tools/perf/perf.c:350 #18 0x55c9400e4a5a in handle_internal_command tools/perf/perf.c:403 #19 0x55c9400e4e22 in run_argv tools/perf/perf.c:447 #20 0x55c9400e53ad in main tools/perf/perf.c:561 #21 0x7f28170456c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #22 0x7f2817045784 in __libc_start_main_impl ../csu/libc-start.c:360 #23 0x55c93ff544c0 in _start (/tmp/perf/perf+0x19a4c0) (BuildId: 84899b0e8c7d3a3eaa67b2eb35e3d8b2f8cd4c93) Address 0x7f2813331920 is located in stack of thread T0 at offset 32 in frame #0 0x55c94046e85e in hist_browser__run ui/browsers/hists.c:746 This frame has 1 object(s): [32, 192) 'title' (line 747) <== Memory access at offset 32 is inside this variable HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork ``` hist_browser__run isn't on the stack so the asan error looks legit. There's no clean init/exit on struct ui_browser so I may be trading a use-after-return for a memory leak, but that seems look a good trade anyway. Fixes: 05e8b08 ("perf ui browser: Stop using 'self'") Signed-off-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Ben Gainey <ben.gainey@arm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Li Dong <lidong@vivo.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Paran Lee <p4ranlee@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Sun Haiyong <sunhaiyong@loongson.cn> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Yanteng Si <siyanteng@loongson.cn> Cc: Yicong Yang <yangyicong@hisilicon.com> Link: https://lore.kernel.org/r/20240507183545.1236093-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

A system crash like this Failing address: 200000cb7df6f000 TEID: 200000cb7df6f403 Fault in home space mode while using kernel ASCE. AS:00000002d71bc007 R3:00000003fe5b8007 S:000000011a446000 P:000000015660c13d Oops: 0038 ilc:3 [#1] PREEMPT SMP Modules linked in: mlx5_ib ... CPU: 8 PID: 7556 Comm: bash Not tainted 6.9.0-rc7 #8 Hardware name: IBM 3931 A01 704 (LPAR) Krnl PSW : 0704e00180000000 0000014b75e7b606 (ap_parse_bitmap_str+0x10e/0x1f8) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000001 ffffffffffffffc0 0000000000000001 00000048f96b75d3 000000cb00000100 ffffffffffffffff ffffffffffffffff 000000cb7df6fce0 000000cb7df6fce0 00000000ffffffff 000000000000002b 00000048ffffffff 000003ff9b2dbc80 200000cb7df6fcd8 0000014bffffffc0 000000cb7df6fbc8 Krnl Code: 0000014b75e7b5fc: a7840047 brc 8,0000014b75e7b68a 0000014b75e7b600: 18b2 lr %r11,%r2 #0000014b75e7b602: a7f4000a brc 15,0000014b75e7b616 >0000014b75e7b606: eb22d00000e6 laog %r2,%r2,0(%r13) 0000014b75e7b60c: a7680001 lhi %r6,1 0000014b75e7b610: 187b lr %r7,%r11 0000014b75e7b612: 84960021 brxh %r9,%r6,0000014b75e7b654 0000014b75e7b616: 18e9 lr %r14,%r9 Call Trace: [<0000014b75e7b606>] ap_parse_bitmap_str+0x10e/0x1f8 ([<0000014b75e7b5dc>] ap_parse_bitmap_str+0xe4/0x1f8) [<0000014b75e7b758>] apmask_store+0x68/0x140 [<0000014b75679196>] kernfs_fop_write_iter+0x14e/0x1e8 [<0000014b75598524>] vfs_write+0x1b4/0x448 [<0000014b7559894c>] ksys_write+0x74/0x100 [<0000014b7618a440>] __do_syscall+0x268/0x328 [<0000014b761a3558>] system_call+0x70/0x98 INFO: lockdep is turned off. Last Breaking-Event-Address: [<0000014b75e7b636>] ap_parse_bitmap_str+0x13e/0x1f8 Kernel panic - not syncing: Fatal exception: panic_on_oops occured when /sys/bus/ap/a[pq]mask was updated with a relative mask value (like +0x10-0x12,+60,-90) with one of the numeric values exceeding INT_MAX. The fix is simple: use unsigned long values for the internal variables. The correct checks are already in place in the function but a simple int for the internal variables was used with the possibility to overflow. Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> Signed-off-by: Harald Freudenberger <freude@linux.ibm.com> Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com> Reviewed-by: Holger Dengler <dengler@linux.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

We have been seeing crashes on duplicate keys in btrfs_set_item_key_safe(): BTRFS critical (device vdb): slot 4 key (450 108 8192) new key (450 108 8192) ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.c:2620! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 3139 Comm: xfs_io Kdump: loaded Not tainted 6.9.0 #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:btrfs_set_item_key_safe+0x11f/0x290 [btrfs] With the following stack trace: #0 btrfs_set_item_key_safe (fs/btrfs/ctree.c:2620:4) #1 btrfs_drop_extents (fs/btrfs/file.c:411:4) #2 log_one_extent (fs/btrfs/tree-log.c:4732:9) #3 btrfs_log_changed_extents (fs/btrfs/tree-log.c:4955:9) #4 btrfs_log_inode (fs/btrfs/tree-log.c:6626:9) #5 btrfs_log_inode_parent (fs/btrfs/tree-log.c:7070:8) #6 btrfs_log_dentry_safe (fs/btrfs/tree-log.c:7171:8) #7 btrfs_sync_file (fs/btrfs/file.c:1933:8) #8 vfs_fsync_range (fs/sync.c:188:9) #9 vfs_fsync (fs/sync.c:202:9) #10 do_fsync (fs/sync.c:212:9) #11 __do_sys_fdatasync (fs/sync.c:225:9) #12 __se_sys_fdatasync (fs/sync.c:223:1) #13 __x64_sys_fdatasync (fs/sync.c:223:1) #14 do_syscall_x64 (arch/x86/entry/common.c:52:14) #15 do_syscall_64 (arch/x86/entry/common.c:83:7) #16 entry_SYSCALL_64+0xaf/0x14c (arch/x86/entry/entry_64.S:121) So we're logging a changed extent from fsync, which is splitting an extent in the log tree. But this split part already exists in the tree, triggering the BUG(). This is the state of the log tree at the time of the crash, dumped with drgn (https://github.com/osandov/drgn/blob/main/contrib/btrfs_tree.py) to get more details than btrfs_print_leaf() gives us: >>> print_extent_buffer(prog.crashed_thread().stack_trace()[0]["eb"]) leaf 33439744 level 0 items 72 generation 9 owner 18446744073709551610 leaf 33439744 flags 0x100000000000000 fs uuid e5bd3946-400c-4223-8923-190ef1f18677 chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da item 0 key (450 INODE_ITEM 0) itemoff 16123 itemsize 160 generation 7 transid 9 size 8192 nbytes 8473563889606862198 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 204 flags 0x10(PREALLOC) atime 1716417703.220000000 (2024-05-22 15:41:43) ctime 1716417704.983333333 (2024-05-22 15:41:44) mtime 1716417704.983333333 (2024-05-22 15:41:44) otime 17592186044416.000000000 (559444-03-08 01:40:16) item 1 key (450 INODE_REF 256) itemoff 16110 itemsize 13 index 195 namelen 3 name: 193 item 2 key (450 XATTR_ITEM 1640047104) itemoff 16073 itemsize 37 location key (0 UNKNOWN.0 0) type XATTR transid 7 data_len 1 name_len 6 name: user.a data a item 3 key (450 EXTENT_DATA 0) itemoff 16020 itemsize 53 generation 9 type 1 (regular) extent data disk byte 303144960 nr 12288 extent data offset 0 nr 4096 ram 12288 extent compression 0 (none) item 4 key (450 EXTENT_DATA 4096) itemoff 15967 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 4096 nr 8192 item 5 key (450 EXTENT_DATA 8192) itemoff 15914 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 8192 nr 4096 ... So the real problem happened earlier: notice that items 4 (4k-12k) and 5 (8k-12k) overlap. Both are prealloc extents. Item 4 straddles i_size and item 5 starts at i_size. Here is the state of the filesystem tree at the time of the crash: >>> root = prog.crashed_thread().stack_trace()[2]["inode"].root >>> ret, nodes, slots = btrfs_search_slot(root, BtrfsKey(450, 0, 0)) >>> print_extent_buffer(nodes[0]) leaf 30425088 level 0 items 184 generation 9 owner 5 leaf 30425088 flags 0x100000000000000 fs uuid e5bd3946-400c-4223-8923-190ef1f18677 chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da ... item 179 key (450 INODE_ITEM 0) itemoff 4907 itemsize 160 generation 7 transid 7 size 4096 nbytes 12288 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 6 flags 0x10(PREALLOC) atime 1716417703.220000000 (2024-05-22 15:41:43) ctime 1716417703.220000000 (2024-05-22 15:41:43) mtime 1716417703.220000000 (2024-05-22 15:41:43) otime 1716417703.220000000 (2024-05-22 15:41:43) item 180 key (450 INODE_REF 256) itemoff 4894 itemsize 13 index 195 namelen 3 name: 193 item 181 key (450 XATTR_ITEM 1640047104) itemoff 4857 itemsize 37 location key (0 UNKNOWN.0 0) type XATTR transid 7 data_len 1 name_len 6 name: user.a data a item 182 key (450 EXTENT_DATA 0) itemoff 4804 itemsize 53 generation 9 type 1 (regular) extent data disk byte 303144960 nr 12288 extent data offset 0 nr 8192 ram 12288 extent compression 0 (none) item 183 key (450 EXTENT_DATA 8192) itemoff 4751 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 8192 nr 4096 Item 5 in the log tree corresponds to item 183 in the filesystem tree, but nothing matches item 4. Furthermore, item 183 is the last item in the leaf. btrfs_log_prealloc_extents() is responsible for logging prealloc extents beyond i_size. It first truncates any previously logged prealloc extents that start beyond i_size. Then, it walks the filesystem tree and copies the prealloc extent items to the log tree. If it hits the end of a leaf, then it calls btrfs_next_leaf(), which unlocks the tree and does another search. However, while the filesystem tree is unlocked, an ordered extent completion may modify the tree. In particular, it may insert an extent item that overlaps with an extent item that was already copied to the log tree. This may manifest in several ways depending on the exact scenario, including an EEXIST error that is silently translated to a full sync, overlapping items in the log tree, or this crash. This particular crash is triggered by the following sequence of events: - Initially, the file has i_size=4k, a regular extent from 0-4k, and a prealloc extent beyond i_size from 4k-12k. The prealloc extent item is the last item in its B-tree leaf. - The file is fsync'd, which copies its inode item and both extent items to the log tree. - An xattr is set on the file, which sets the BTRFS_INODE_COPY_EVERYTHING flag. - The range 4k-8k in the file is written using direct I/O. i_size is extended to 8k, but the ordered extent is still in flight. - The file is fsync'd. Since BTRFS_INODE_COPY_EVERYTHING is set, this calls copy_inode_items_to_log(), which calls btrfs_log_prealloc_extents(). - btrfs_log_prealloc_extents() finds the 4k-12k prealloc extent in the filesystem tree. Since it starts before i_size, it skips it. Since it is the last item in its B-tree leaf, it calls btrfs_next_leaf(). - btrfs_next_leaf() unlocks the path. - The ordered extent completion runs, which converts the 4k-8k part of the prealloc extent to written and inserts the remaining prealloc part from 8k-12k. - btrfs_next_leaf() does a search and finds the new prealloc extent 8k-12k. - btrfs_log_prealloc_extents() copies the 8k-12k prealloc extent into the log tree. Note that it overlaps with the 4k-12k prealloc extent that was copied to the log tree by the first fsync. - fsync calls btrfs_log_changed_extents(), which tries to log the 4k-8k extent that was written. - This tries to drop the range 4k-8k in the log tree, which requires adjusting the start of the 4k-12k prealloc extent in the log tree to 8k. - btrfs_set_item_key_safe() sees that there is already an extent starting at 8k in the log tree and calls BUG(). Fix this by detecting when we're about to insert an overlapping file extent item in the log tree and truncating the part that would overlap. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>

We have been seeing crashes on duplicate keys in btrfs_set_item_key_safe(): BTRFS critical (device vdb): slot 4 key (450 108 8192) new key (450 108 8192) ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.c:2620! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 3139 Comm: xfs_io Kdump: loaded Not tainted 6.9.0 #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:btrfs_set_item_key_safe+0x11f/0x290 [btrfs] With the following stack trace: #0 btrfs_set_item_key_safe (fs/btrfs/ctree.c:2620:4) #1 btrfs_drop_extents (fs/btrfs/file.c:411:4) #2 log_one_extent (fs/btrfs/tree-log.c:4732:9) #3 btrfs_log_changed_extents (fs/btrfs/tree-log.c:4955:9) #4 btrfs_log_inode (fs/btrfs/tree-log.c:6626:9) #5 btrfs_log_inode_parent (fs/btrfs/tree-log.c:7070:8) #6 btrfs_log_dentry_safe (fs/btrfs/tree-log.c:7171:8) #7 btrfs_sync_file (fs/btrfs/file.c:1933:8) #8 vfs_fsync_range (fs/sync.c:188:9) #9 vfs_fsync (fs/sync.c:202:9) #10 do_fsync (fs/sync.c:212:9) #11 __do_sys_fdatasync (fs/sync.c:225:9) #12 __se_sys_fdatasync (fs/sync.c:223:1) #13 __x64_sys_fdatasync (fs/sync.c:223:1) #14 do_syscall_x64 (arch/x86/entry/common.c:52:14) #15 do_syscall_64 (arch/x86/entry/common.c:83:7) #16 entry_SYSCALL_64+0xaf/0x14c (arch/x86/entry/entry_64.S:121) So we're logging a changed extent from fsync, which is splitting an extent in the log tree. But this split part already exists in the tree, triggering the BUG(). This is the state of the log tree at the time of the crash, dumped with drgn (https://github.com/osandov/drgn/blob/main/contrib/btrfs_tree.py) to get more details than btrfs_print_leaf() gives us: >>> print_extent_buffer(prog.crashed_thread().stack_trace()[0]["eb"]) leaf 33439744 level 0 items 72 generation 9 owner 18446744073709551610 leaf 33439744 flags 0x100000000000000 fs uuid e5bd3946-400c-4223-8923-190ef1f18677 chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da item 0 key (450 INODE_ITEM 0) itemoff 16123 itemsize 160 generation 7 transid 9 size 8192 nbytes 8473563889606862198 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 204 flags 0x10(PREALLOC) atime 1716417703.220000000 (2024-05-22 15:41:43) ctime 1716417704.983333333 (2024-05-22 15:41:44) mtime 1716417704.983333333 (2024-05-22 15:41:44) otime 17592186044416.000000000 (559444-03-08 01:40:16) item 1 key (450 INODE_REF 256) itemoff 16110 itemsize 13 index 195 namelen 3 name: 193 item 2 key (450 XATTR_ITEM 1640047104) itemoff 16073 itemsize 37 location key (0 UNKNOWN.0 0) type XATTR transid 7 data_len 1 name_len 6 name: user.a data a item 3 key (450 EXTENT_DATA 0) itemoff 16020 itemsize 53 generation 9 type 1 (regular) extent data disk byte 303144960 nr 12288 extent data offset 0 nr 4096 ram 12288 extent compression 0 (none) item 4 key (450 EXTENT_DATA 4096) itemoff 15967 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 4096 nr 8192 item 5 key (450 EXTENT_DATA 8192) itemoff 15914 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 8192 nr 4096 ... So the real problem happened earlier: notice that items 4 (4k-12k) and 5 (8k-12k) overlap. Both are prealloc extents. Item 4 straddles i_size and item 5 starts at i_size. Here is the state of the filesystem tree at the time of the crash: >>> root = prog.crashed_thread().stack_trace()[2]["inode"].root >>> ret, nodes, slots = btrfs_search_slot(root, BtrfsKey(450, 0, 0)) >>> print_extent_buffer(nodes[0]) leaf 30425088 level 0 items 184 generation 9 owner 5 leaf 30425088 flags 0x100000000000000 fs uuid e5bd3946-400c-4223-8923-190ef1f18677 chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da ... item 179 key (450 INODE_ITEM 0) itemoff 4907 itemsize 160 generation 7 transid 7 size 4096 nbytes 12288 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 6 flags 0x10(PREALLOC) atime 1716417703.220000000 (2024-05-22 15:41:43) ctime 1716417703.220000000 (2024-05-22 15:41:43) mtime 1716417703.220000000 (2024-05-22 15:41:43) otime 1716417703.220000000 (2024-05-22 15:41:43) item 180 key (450 INODE_REF 256) itemoff 4894 itemsize 13 index 195 namelen 3 name: 193 item 181 key (450 XATTR_ITEM 1640047104) itemoff 4857 itemsize 37 location key (0 UNKNOWN.0 0) type XATTR transid 7 data_len 1 name_len 6 name: user.a data a item 182 key (450 EXTENT_DATA 0) itemoff 4804 itemsize 53 generation 9 type 1 (regular) extent data disk byte 303144960 nr 12288 extent data offset 0 nr 8192 ram 12288 extent compression 0 (none) item 183 key (450 EXTENT_DATA 8192) itemoff 4751 itemsize 53 generation 9 type 2 (prealloc) prealloc data disk byte 303144960 nr 12288 prealloc data offset 8192 nr 4096 Item 5 in the log tree corresponds to item 183 in the filesystem tree, but nothing matches item 4. Furthermore, item 183 is the last item in the leaf. btrfs_log_prealloc_extents() is responsible for logging prealloc extents beyond i_size. It first truncates any previously logged prealloc extents that start beyond i_size. Then, it walks the filesystem tree and copies the prealloc extent items to the log tree. If it hits the end of a leaf, then it calls btrfs_next_leaf(), which unlocks the tree and does another search. However, while the filesystem tree is unlocked, an ordered extent completion may modify the tree. In particular, it may insert an extent item that overlaps with an extent item that was already copied to the log tree. This may manifest in several ways depending on the exact scenario, including an EEXIST error that is silently translated to a full sync, overlapping items in the log tree, or this crash. This particular crash is triggered by the following sequence of events: - Initially, the file has i_size=4k, a regular extent from 0-4k, and a prealloc extent beyond i_size from 4k-12k. The prealloc extent item is the last item in its B-tree leaf. - The file is fsync'd, which copies its inode item and both extent items to the log tree. - An xattr is set on the file, which sets the BTRFS_INODE_COPY_EVERYTHING flag. - The range 4k-8k in the file is written using direct I/O. i_size is extended to 8k, but the ordered extent is still in flight. - The file is fsync'd. Since BTRFS_INODE_COPY_EVERYTHING is set, this calls copy_inode_items_to_log(), which calls btrfs_log_prealloc_extents(). - btrfs_log_prealloc_extents() finds the 4k-12k prealloc extent in the filesystem tree. Since it starts before i_size, it skips it. Since it is the last item in its B-tree leaf, it calls btrfs_next_leaf(). - btrfs_next_leaf() unlocks the path. - The ordered extent completion runs, which converts the 4k-8k part of the prealloc extent to written and inserts the remaining prealloc part from 8k-12k. - btrfs_next_leaf() does a search and finds the new prealloc extent 8k-12k. - btrfs_log_prealloc_extents() copies the 8k-12k prealloc extent into the log tree. Note that it overlaps with the 4k-12k prealloc extent that was copied to the log tree by the first fsync. - fsync calls btrfs_log_changed_extents(), which tries to log the 4k-8k extent that was written. - This tries to drop the range 4k-8k in the log tree, which requires adjusting the start of the 4k-12k prealloc extent in the log tree to 8k. - btrfs_set_item_key_safe() sees that there is already an extent starting at 8k in the log tree and calls BUG(). Fix this by detecting when we're about to insert an overlapping file extent item in the log tree and truncating the part that would overlap. CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>

…PLES event" This reverts commit 7d1405c. This causes segfaults in some cases, as reported by Milian: ``` sudo /usr/bin/perf record -z --call-graph dwarf -e cycles -e raw_syscalls:sys_enter ls ... [ perf record: Woken up 3 times to write data ] malloc(): invalid next size (unsorted) Aborted ``` Backtrace with GDB + debuginfod: ``` malloc(): invalid next size (unsorted) Thread 1 "perf" received signal SIGABRT, Aborted. __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44 Downloading source file /usr/src/debug/glibc/glibc/nptl/pthread_kill.c 44 return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0; (gdb) bt #0 __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44 #1 0x00007ffff6ea8eb3 in __pthread_kill_internal (threadid=<optimized out>, signo=6) at pthread_kill.c:78 #2 0x00007ffff6e50a30 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/ raise.c:26 #3 0x00007ffff6e384c3 in __GI_abort () at abort.c:79 #4 0x00007ffff6e39354 in __libc_message_impl (fmt=fmt@entry=0x7ffff6fc22ea "%s\n") at ../sysdeps/posix/libc_fatal.c:132 #5 0x00007ffff6eb3085 in malloc_printerr (str=str@entry=0x7ffff6fc5850 "malloc(): invalid next size (unsorted)") at malloc.c:5772 #6 0x00007ffff6eb657c in _int_malloc (av=av@entry=0x7ffff6ff6ac0 <main_arena>, bytes=bytes@entry=368) at malloc.c:4081 #7 0x00007ffff6eb877e in __libc_calloc (n=<optimized out>, elem_size=<optimized out>) at malloc.c:3754 #8 0x000055555569bdb6 in perf_session.do_write_header () #9 0x00005555555a373a in __cmd_record.constprop.0 () #10 0x00005555555a6846 in cmd_record () #11 0x000055555564db7f in run_builtin () #12 0x000055555558ed77 in main () ``` Valgrind memcheck: ``` ==45136== Invalid write of size 8 ==45136== at 0x2B38A5: perf_event__synthesize_id_sample (in /usr/bin/perf) ==45136== by 0x157069: __cmd_record.constprop.0 (in /usr/bin/perf) ==45136== by 0x15A845: cmd_record (in /usr/bin/perf) ==45136== by 0x201B7E: run_builtin (in /usr/bin/perf) ==45136== by 0x142D76: main (in /usr/bin/perf) ==45136== Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd ==45136== at 0x4849BF3: calloc (vg_replace_malloc.c:1675) ==45136== by 0x3574AB: zalloc (in /usr/bin/perf) ==45136== by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf) ==45136== by 0x15A845: cmd_record (in /usr/bin/perf) ==45136== by 0x201B7E: run_builtin (in /usr/bin/perf) ==45136== by 0x142D76: main (in /usr/bin/perf) ==45136== ==45136== Syscall param write(buf) points to unaddressable byte(s) ==45136== at 0x575953D: __libc_write (write.c:26) ==45136== by 0x575953D: write (write.c:24) ==45136== by 0x35761F: ion (in /usr/bin/perf) ==45136== by 0x357778: writen (in /usr/bin/perf) ==45136== by 0x1548F7: record__write (in /usr/bin/perf) ==45136== by 0x15708A: __cmd_record.constprop.0 (in /usr/bin/perf) ==45136== by 0x15A845: cmd_record (in /usr/bin/perf) ==45136== by 0x201B7E: run_builtin (in /usr/bin/perf) ==45136== by 0x142D76: main (in /usr/bin/perf) ==45136== Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd ==45136== at 0x4849BF3: calloc (vg_replace_malloc.c:1675) ==45136== by 0x3574AB: zalloc (in /usr/bin/perf) ==45136== by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf) ==45136== by 0x15A845: cmd_record (in /usr/bin/perf) ==45136== by 0x201B7E: run_builtin (in /usr/bin/perf) ==45136== by 0x142D76: main (in /usr/bin/perf) ==45136== ----- Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/ Reported-by: Milian Wolff <milian.wolff@kdab.com> Tested-by: Milian Wolff <milian.wolff@kdab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: stable@kernel.org # 6.8+ Link: https://lore.kernel.org/lkml/Zl9ksOlHJHnKM70p@x1 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The code in ocfs2_dio_end_io_write() estimates number of necessary transaction credits using ocfs2_calc_extend_credits(). This however does not take into account that the IO could be arbitrarily large and can contain arbitrary number of extents. Extent tree manipulations do often extend the current transaction but not in all of the cases. For example if we have only single block extents in the tree, ocfs2_mark_extent_written() will end up calling ocfs2_replace_extent_rec() all the time and we will never extend the current transaction and eventually exhaust all the transaction credits if the IO contains many single block extents. Once that happens a WARN_ON(jbd2_handle_buffer_credits(handle) <= 0) is triggered in jbd2_journal_dirty_metadata() and subsequently OCFS2 aborts in response to this error. This was actually triggered by one of our customers on a heavily fragmented OCFS2 filesystem. To fix the issue make sure the transaction always has enough credits for one extent insert before each call of ocfs2_mark_extent_written(). Heming Zhao said: ------ PANIC: "Kernel panic - not syncing: OCFS2: (device dm-1): panic forced after error" PID: xxx TASK: xxxx CPU: 5 COMMAND: "SubmitThread-CA" #0 machine_kexec at ffffffff8c069932 #1 __crash_kexec at ffffffff8c1338fa #2 panic at ffffffff8c1d69b9 #3 ocfs2_handle_error at ffffffffc0c86c0c [ocfs2] #4 __ocfs2_abort at ffffffffc0c88387 [ocfs2] #5 ocfs2_journal_dirty at ffffffffc0c51e98 [ocfs2] #6 ocfs2_split_extent at ffffffffc0c27ea3 [ocfs2] #7 ocfs2_change_extent_flag at ffffffffc0c28053 [ocfs2] #8 ocfs2_mark_extent_written at ffffffffc0c28347 [ocfs2] #9 ocfs2_dio_end_io_write at ffffffffc0c2bef9 [ocfs2] #10 ocfs2_dio_end_io at ffffffffc0c2c0f5 [ocfs2] #11 dio_complete at ffffffff8c2b9fa7 #12 do_blockdev_direct_IO at ffffffff8c2bc09f #13 ocfs2_direct_IO at ffffffffc0c2b653 [ocfs2] #14 generic_file_direct_write at ffffffff8c1dcf14 #15 __generic_file_write_iter at ffffffff8c1dd07b #16 ocfs2_file_write_iter at ffffffffc0c49f1f [ocfs2] #17 aio_write at ffffffff8c2cc72e #18 kmem_cache_alloc at ffffffff8c248dde #19 do_io_submit at ffffffff8c2ccada #20 do_syscall_64 at ffffffff8c004984 #21 entry_SYSCALL_64_after_hwframe at ffffffff8c8000ba Link: https://lkml.kernel.org/r/20240617095543.6971-1-jack@suse.cz Link: https://lkml.kernel.org/r/20240614145243.8837-1-jack@suse.cz Fixes: c15471f ("ocfs2: fix sparse file & data ordering issue in direct io") Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Heming Zhao <heming.zhao@suse.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Currently if we request a feature that is not set in the Kernel config we fail silently and return all the available features. However, the man page indicates we should return an EINVAL. We need to fix this issue since we can end up with a Kernel warning should a program request the feature UFFD_FEATURE_WP_UNPOPULATED on a kernel with the config not set with this feature. [ 200.812896] WARNING: CPU: 91 PID: 13634 at mm/memory.c:1660 zap_pte_range+0x43d/0x660 [ 200.820738] Modules linked in: [ 200.869387] CPU: 91 PID: 13634 Comm: userfaultfd Kdump: loaded Not tainted 6.9.0-rc5+ #8 [ 200.877477] Hardware name: Dell Inc. PowerEdge R6525/0N7YGH, BIOS 2.7.3 03/30/2022 [ 200.885052] RIP: 0010:zap_pte_range+0x43d/0x660 Link: https://lkml.kernel.org/r/20240621181224.3881179-1-audra@redhat.com Fixes: e06f1e1 ("userfaultfd: wp: enabled write protection in userfaultfd API") Signed-off-by: Audra Mitchell <audra@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Shaohua Li <shli@fb.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The test thread will start N benchmark kthreads and then schedule out until the test time finished and notify the benchmark kthreads to stop. The benchmark kthreads will keep running until notified to stop. There's a problem with current implementation when the benchmark kthreads number is equal to the CPUs on a non-preemptible kernel: since the scheduler will balance the kthreads across the CPUs and when the test time's out the test thread won't get a chance to be scheduled on any CPU then cannot notify the benchmark kthreads to stop. This can be easily reproduced on a VM (simulated with 16 CPUs) with PREEMPT_VOLUNTARY: estuary:/mnt$ ./dma_map_benchmark -t 16 -s 1 rcu: INFO: rcu_sched self-detected stall on CPU rcu: 10-...!: (5221 ticks this GP) idle=ed24/1/0x4000000000000000 softirq=142/142 fqs=0 rcu: (t=5254 jiffies g=-559 q=45 ncpus=16) rcu: rcu_sched kthread starved for 5255 jiffies! g-559 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=12 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_sched state:R running task stack:0 pid:16 tgid:16 ppid:2 flags:0x00000008 Call trace __switch_to+0xec/0x138 __schedule+0x2f8/0x1080 schedule+0x30/0x130 schedule_timeout+0xa0/0x188 rcu_gp_fqs_loop+0x128/0x528 rcu_gp_kthread+0x1c8/0x208 kthread+0xec/0xf8 ret_from_fork+0x10/0x20 Sending NMI from CPU 10 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 332 Comm: dma-map-benchma Not tainted 6.10.0-rc1-vanilla-LSE #8 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : arm_smmu_cmdq_issue_cmdlist+0x218/0x730 lr : arm_smmu_cmdq_issue_cmdlist+0x488/0x730 sp : ffff80008748b630 x29: ffff80008748b630 x28: 0000000000000000 x27: ffff80008748b780 x26: 0000000000000000 x25: 000000000000bc70 x24: 000000000001bc70 x23: ffff0000c12af080 x22: 0000000000010000 x21: 000000000000ffff x20: ffff80008748b700 x19: ffff0000c12af0c0 x18: 0000000000010000 x17: 0000000000000001 x16: 0000000000000040 x15: ffffffffffffffff x14: 0001ffffffffffff x13: 000000000000ffff x12: 00000000000002f1 x11: 000000000001ffff x10: 0000000000000031 x9 : ffff800080b6b0b8 x8 : ffff0000c2a48000 x7 : 000000000001bc71 x6 : 0001800000000000 x5 : 00000000000002f1 x4 : 01ffffffffffffff x3 : 000000000009aaf1 x2 : 0000000000000018 x1 : 000000000000000f x0 : ffff0000c12af18c Call trace: arm_smmu_cmdq_issue_cmdlist+0x218/0x730 __arm_smmu_tlb_inv_range+0xe0/0x1a8 arm_smmu_iotlb_sync+0xc0/0x128 __iommu_dma_unmap+0x248/0x320 iommu_dma_unmap_page+0x5c/0xe8 dma_unmap_page_attrs+0x38/0x1d0 map_benchmark_thread+0x118/0x2c0 kthread+0xec/0xf8 ret_from_fork+0x10/0x20 Solve this by adding scheduling point in the kthread loop, so if there're other threads in the system they may have a chance to run, especially the thread to notify the test end. However this may degrade the test concurrency so it's recommended to run this on an idle system. Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Acked-by: Barry Song <baohua@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de>

Add a set of tests to validate that stack traces captured from or in the presence of active uprobes and uretprobes are valid and complete. For this we use BPF program that are installed either on entry or exit of user function, plus deep-nested USDT. One of target funtions (target_1) is recursive to generate two different entries in the stack trace for the same uprobe/uretprobe, testing potential edge conditions. If there is no fixes, we get something like this for one of the scenarios: caller: 0x758fff - 0x7595ab target_1: 0x758fd5 - 0x758fff target_2: 0x758fca - 0x758fd5 target_3: 0x758fbf - 0x758fca target_4: 0x758fb3 - 0x758fbf ENTRY #0: 0x758fb3 (in target_4) ENTRY #1: 0x758fd3 (in target_2) ENTRY #2: 0x758ffd (in target_1) ENTRY #3: 0x7fffffffe000 ENTRY #4: 0x7fffffffe000 ENTRY #5: 0x6f8f39 ENTRY #6: 0x6fa6f0 ENTRY #7: 0x7f403f229590 Entry #3 and #4 (0x7fffffffe000) are uretprobe trampoline addresses which obscure actual target_1 and another target_1 invocations. Also note that between entry #0 and entry #1 we are missing an entry for target_3. With fixes, we get desired full stack traces: caller: 0x758fff - 0x7595ab target_1: 0x758fd5 - 0x758fff target_2: 0x758fca - 0x758fd5 target_3: 0x758fbf - 0x758fca target_4: 0x758fb3 - 0x758fbf ENTRY #0: 0x758fb7 (in target_4) ENTRY #1: 0x758fc8 (in target_3) ENTRY #2: 0x758fd3 (in target_2) ENTRY #3: 0x758ffd (in target_1) ENTRY #4: 0x758ff3 (in target_1) ENTRY #5: 0x75922c (in caller) ENTRY #6: 0x6f8f39 ENTRY #7: 0x6fa6f0 ENTRY #8: 0x7f986adc4cd0 Now there is a logical and complete sequence of function calls. Link: https://lore.kernel.org/all/20240522013845.1631305-5-andrii@kernel.org/ Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

iter_finish_branch_entry() doesn't put the branch_info from/to map elements creating memory leaks. This can be seen with: ``` $ perf record -e cycles -b perf test -w noploop $ perf report -D ... Direct leak of 984344 byte(s) in 123043 object(s) allocated from: #0 0x7fb2654f3bd7 in malloc libsanitizer/asan/asan_malloc_linux.cpp:69 #1 0x564d3400d10b in map__get util/map.h:186 #2 0x564d3400d10b in ip__resolve_ams util/machine.c:1981 #3 0x564d34014d81 in sample__resolve_bstack util/machine.c:2151 #4 0x564d34094790 in iter_prepare_branch_entry util/hist.c:898 #5 0x564d34098fa4 in hist_entry_iter__add util/hist.c:1238 #6 0x564d33d1f0c7 in process_sample_event tools/perf/builtin-report.c:334 #7 0x564d34031eb7 in perf_session__deliver_event util/session.c:1655 #8 0x564d3403ba52 in do_flush util/ordered-events.c:245 #9 0x564d3403ba52 in __ordered_events__flush util/ordered-events.c:324 #10 0x564d3402d32e in perf_session__process_user_event util/session.c:1708 #11 0x564d34032480 in perf_session__process_event util/session.c:1877 #12 0x564d340336ad in reader__read_event util/session.c:2399 #13 0x564d34033fdc in reader__process_events util/session.c:2448 #14 0x564d34033fdc in __perf_session__process_events util/session.c:2495 #15 0x564d34033fdc in perf_session__process_events util/session.c:2661 #16 0x564d33d27113 in __cmd_report tools/perf/builtin-report.c:1065 #17 0x564d33d27113 in cmd_report tools/perf/builtin-report.c:1805 #18 0x564d33e0ccb7 in run_builtin tools/perf/perf.c:350 #19 0x564d33e0d45e in handle_internal_command tools/perf/perf.c:403 #20 0x564d33cdd827 in run_argv tools/perf/perf.c:447 #21 0x564d33cdd827 in main tools/perf/perf.c:561 ... ``` Clearing up the map_symbols properly creates maps reference count issues so resolve those. Resolving this issue doesn't improve peak heap consumption for the test above. Committer testing: $ sudo dnf install libasan $ make -k CORESIGHT=1 EXTRA_CFLAGS="-fsanitize=address" CC=clang O=/tmp/build/$(basename $PWD)/ -C tools/perf install-bin Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sun Haiyong <sunhaiyong@loongson.cn> Cc: Yanteng Si <siyanteng@loongson.cn> Link: https://lore.kernel.org/r/20240807065136.1039977-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When l2tp tunnels use a socket provided by userspace, we can hit lockdep splats like the below when data is transmitted through another (unrelated) userspace socket which then gets routed over l2tp. This issue was previously discussed here: https://lore.kernel.org/netdev/87sfialu2n.fsf@cloudflare.com/ The solution is to have lockdep treat socket locks of l2tp tunnel sockets separately than those of standard INET sockets. To do so, use a different lockdep subclass where lock nesting is possible. ============================================ WARNING: possible recursive locking detected 6.10.0+ #34 Not tainted -------------------------------------------- iperf3/771 is trying to acquire lock: ffff8881027601d8 (slock-AF_INET/1){+.-.}-{2:2}, at: l2tp_xmit_skb+0x243/0x9d0 but task is already holding lock: ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(slock-AF_INET/1); lock(slock-AF_INET/1); *** DEADLOCK *** May be due to missing lock nesting notation 10 locks held by iperf3/771: #0: ffff888102650258 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x1a/0x40 #1: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0 #2: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130 #3: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x28b/0x9f0 #4: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0xf9/0x260 #5: ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10 #6: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0 #7: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130 #8: ffffffff822ac1e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0xcc/0x1450 #9: ffff888101f33258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x513/0x1450 stack backtrace: CPU: 2 UID: 0 PID: 771 Comm: iperf3 Not tainted 6.10.0+ #34 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x69/0xa0 dump_stack+0xc/0x20 __lock_acquire+0x135d/0x2600 ? srso_alias_return_thunk+0x5/0xfbef5 lock_acquire+0xc4/0x2a0 ? l2tp_xmit_skb+0x243/0x9d0 ? __skb_checksum+0xa3/0x540 _raw_spin_lock_nested+0x35/0x50 ? l2tp_xmit_skb+0x243/0x9d0 l2tp_xmit_skb+0x243/0x9d0 l2tp_eth_dev_xmit+0x3c/0xc0 dev_hard_start_xmit+0x11e/0x420 sch_direct_xmit+0xc3/0x640 __dev_queue_xmit+0x61c/0x1450 ? ip_finish_output2+0xf4c/0x1130 ip_finish_output2+0x6b6/0x1130 ? srso_alias_return_thunk+0x5/0xfbef5 ? __ip_finish_output+0x217/0x380 ? srso_alias_return_thunk+0x5/0xfbef5 __ip_finish_output+0x217/0x380 ip_output+0x99/0x120 __ip_queue_xmit+0xae4/0xbc0 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? tcp_options_write.constprop.0+0xcb/0x3e0 ip_queue_xmit+0x34/0x40 __tcp_transmit_skb+0x1625/0x1890 __tcp_send_ack+0x1b8/0x340 tcp_send_ack+0x23/0x30 __tcp_ack_snd_check+0xa8/0x530 ? srso_alias_return_thunk+0x5/0xfbef5 tcp_rcv_established+0x412/0xd70 tcp_v4_do_rcv+0x299/0x420 tcp_v4_rcv+0x1991/0x1e10 ip_protocol_deliver_rcu+0x50/0x220 ip_local_deliver_finish+0x158/0x260 ip_local_deliver+0xc8/0xe0 ip_rcv+0xe5/0x1d0 ? __pfx_ip_rcv+0x10/0x10 __netif_receive_skb_one_core+0xce/0xe0 ? process_backlog+0x28b/0x9f0 __netif_receive_skb+0x34/0xd0 ? process_backlog+0x28b/0x9f0 process_backlog+0x2cb/0x9f0 __napi_poll.constprop.0+0x61/0x280 net_rx_action+0x332/0x670 ? srso_alias_return_thunk+0x5/0xfbef5 ? find_held_lock+0x2b/0x80 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 handle_softirqs+0xda/0x480 ? __dev_queue_xmit+0xa2c/0x1450 do_softirq+0xa1/0xd0 </IRQ> <TASK> __local_bh_enable_ip+0xc8/0xe0 ? __dev_queue_xmit+0xa2c/0x1450 __dev_queue_xmit+0xa48/0x1450 ? ip_finish_output2+0xf4c/0x1130 ip_finish_output2+0x6b6/0x1130 ? srso_alias_return_thunk+0x5/0xfbef5 ? __ip_finish_output+0x217/0x380 ? srso_alias_return_thunk+0x5/0xfbef5 __ip_finish_output+0x217/0x380 ip_output+0x99/0x120 __ip_queue_xmit+0xae4/0xbc0 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? tcp_options_write.constprop.0+0xcb/0x3e0 ip_queue_xmit+0x34/0x40 __tcp_transmit_skb+0x1625/0x1890 tcp_write_xmit+0x766/0x2fb0 ? __entry_text_end+0x102ba9/0x102bad ? srso_alias_return_thunk+0x5/0xfbef5 ? __might_fault+0x74/0xc0 ? srso_alias_return_thunk+0x5/0xfbef5 __tcp_push_pending_frames+0x56/0x190 tcp_push+0x117/0x310 tcp_sendmsg_locked+0x14c1/0x1740 tcp_sendmsg+0x28/0x40 inet_sendmsg+0x5d/0x90 sock_write_iter+0x242/0x2b0 vfs_write+0x68d/0x800 ? __pfx_sock_write_iter+0x10/0x10 ksys_write+0xc8/0xf0 __x64_sys_write+0x3d/0x50 x64_sys_call+0xfaf/0x1f50 do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f4d143af992 Code: c3 8b 07 85 c0 75 24 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> e9 01 cc ff ff 41 54 b8 02 00 00 0 RSP: 002b:00007ffd65032058 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f4d143af992 RDX: 0000000000000025 RSI: 00007f4d143f3bcc RDI: 0000000000000005 RBP: 00007f4d143f2b28 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4d143f3bcc R13: 0000000000000005 R14: 0000000000000000 R15: 00007ffd650323f0 </TASK> Fixes: 0b2c597 ("l2tp: close all race conditions in l2tp_tunnel_register()") Suggested-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot+6acef9e0a4d1f46c83d4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6acef9e0a4d1f46c83d4 CC: gnault@redhat.com CC: cong.wang@bytedance.com Signed-off-by: James Chapman <jchapman@katalix.com> Signed-off-by: Tom Parkin <tparkin@katalix.com> Link: https://patch.msgid.link/20240806160626.1248317-1-jchapman@katalix.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

iter_finish_branch_entry() doesn't put the branch_info from/to map elements creating memory leaks. This can be seen with: ``` $ perf record -e cycles -b perf test -w noploop $ perf report -D ... Direct leak of 984344 byte(s) in 123043 object(s) allocated from: #0 0x7fb2654f3bd7 in malloc libsanitizer/asan/asan_malloc_linux.cpp:69 #1 0x564d3400d10b in map__get util/map.h:186 #2 0x564d3400d10b in ip__resolve_ams util/machine.c:1981 #3 0x564d34014d81 in sample__resolve_bstack util/machine.c:2151 #4 0x564d34094790 in iter_prepare_branch_entry util/hist.c:898 #5 0x564d34098fa4 in hist_entry_iter__add util/hist.c:1238 #6 0x564d33d1f0c7 in process_sample_event tools/perf/builtin-report.c:334 #7 0x564d34031eb7 in perf_session__deliver_event util/session.c:1655 #8 0x564d3403ba52 in do_flush util/ordered-events.c:245 #9 0x564d3403ba52 in __ordered_events__flush util/ordered-events.c:324 #10 0x564d3402d32e in perf_session__process_user_event util/session.c:1708 #11 0x564d34032480 in perf_session__process_event util/session.c:1877 #12 0x564d340336ad in reader__read_event util/session.c:2399 #13 0x564d34033fdc in reader__process_events util/session.c:2448 #14 0x564d34033fdc in __perf_session__process_events util/session.c:2495 #15 0x564d34033fdc in perf_session__process_events util/session.c:2661 #16 0x564d33d27113 in __cmd_report tools/perf/builtin-report.c:1065 #17 0x564d33d27113 in cmd_report tools/perf/builtin-report.c:1805 #18 0x564d33e0ccb7 in run_builtin tools/perf/perf.c:350 #19 0x564d33e0d45e in handle_internal_command tools/perf/perf.c:403 #20 0x564d33cdd827 in run_argv tools/perf/perf.c:447 #21 0x564d33cdd827 in main tools/perf/perf.c:561 ... ``` Clearing up the map_symbols properly creates maps reference count issues so resolve those. Resolving this issue doesn't improve peak heap consumption for the test above. Committer testing: $ sudo dnf install libasan $ make -k CORESIGHT=1 EXTRA_CFLAGS="-fsanitize=address" CC=clang O=/tmp/build/$(basename $PWD)/ -C tools/perf install-bin Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sun Haiyong <sunhaiyong@loongson.cn> Cc: Yanteng Si <siyanteng@loongson.cn> Link: https://lore.kernel.org/r/20240807065136.1039977-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

AddressSanitizer found a use-after-free bug in the symbol code which manifested as 'perf top' segfaulting. ==1238389==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b00c48844b at pc 0x5650d8035961 bp 0x7f751aaecc90 sp 0x7f751aaecc80 READ of size 1 at 0x60b00c48844b thread T193 #0 0x5650d8035960 in _sort__sym_cmp util/sort.c:310 #1 0x5650d8043744 in hist_entry__cmp util/hist.c:1286 #2 0x5650d8043951 in hists__findnew_entry util/hist.c:614 #3 0x5650d804568f in __hists__add_entry util/hist.c:754 #4 0x5650d8045bf9 in hists__add_entry util/hist.c:772 #5 0x5650d8045df1 in iter_add_single_normal_entry util/hist.c:997 #6 0x5650d8043326 in hist_entry_iter__add util/hist.c:1242 #7 0x5650d7ceeefe in perf_event__process_sample /home/matt/src/linux/tools/perf/builtin-top.c:845 #8 0x5650d7ceeefe in deliver_event /home/matt/src/linux/tools/perf/builtin-top.c:1208 #9 0x5650d7fdb51b in do_flush util/ordered-events.c:245 #10 0x5650d7fdb51b in __ordered_events__flush util/ordered-events.c:324 #11 0x5650d7ced743 in process_thread /home/matt/src/linux/tools/perf/builtin-top.c:1120 #12 0x7f757ef1f133 in start_thread nptl/pthread_create.c:442 #13 0x7f757ef9f7db in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 When updating hist maps it's also necessary to update the hist symbol reference because the old one gets freed in map__put(). While this bug was probably introduced with 5c24b67 ("perf tools: Replace map->referenced & maps->removed_maps with map->refcnt"), the symbol objects were leaked until c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL") was merged so the bug was masked. Fixes: c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL") Reported-by: Yunzhao Li <yunzhao@cloudflare.com> Signed-off-by: Matt Fleming (Cloudflare) <matt@readmodwrite.com> Cc: Ian Rogers <irogers@google.com> Cc: kernel-team@cloudflare.com Cc: Namhyung Kim <namhyung@kernel.org> Cc: Riccardo Mancini <rickyman7@gmail.com> Cc: stable@vger.kernel.org # v5.13+ Link: https://lore.kernel.org/r/20240815142212.3834625-1-matt@readmodwrite.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock on x86 due to a chain of locks and SRCU synchronizations. Translating the below lockdep splat, CPU1 #6 will wait on CPU0 #1, CPU0 #8 will wait on CPU2 #3, and CPU2 #7 will wait on CPU1 #4 (if there's a writer, due to the fairness of r/w semaphores). CPU0 CPU1 CPU2 1 lock(&kvm->slots_lock); 2 lock(&vcpu->mutex); 3 lock(&kvm->srcu); 4 lock(cpu_hotplug_lock); 5 lock(kvm_lock); 6 lock(&kvm->slots_lock); 7 lock(cpu_hotplug_lock); 8 sync(&kvm->srcu); Note, there are likely more potential deadlocks in KVM x86, e.g. the same pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with __kvmclock_cpufreq_notifier(): cpuhp_cpufreq_online() | -> cpufreq_online() | -> cpufreq_gov_performance_limits() | -> __cpufreq_driver_target() | -> __target_index() | -> cpufreq_freq_transition_begin() | -> cpufreq_notify_transition() | -> ... __kvmclock_cpufreq_notifier() But, actually triggering such deadlocks is beyond rare due to the combination of dependencies and timings involved. E.g. the cpufreq notifier is only used on older CPUs without a constant TSC, mucking with the NX hugepage mitigation while VMs are running is very uncommon, and doing so while also onlining/offlining a CPU (necessary to generate contention on cpu_hotplug_lock) would be even more unusual. The most robust solution to the general cpu_hotplug_lock issue is likely to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq notifier doesn't to take kvm_lock. For now, settle for fixing the most blatant deadlock, as switching to an RCU-protected list is a much more involved change, but add a comment in locking.rst to call out that care needs to be taken when walking holding kvm_lock and walking vm_list. ====================================================== WARNING: possible circular locking dependency detected 6.10.0-smp--c257535a0c9d-pip #330 Tainted: G S O ------------------------------------------------------ tee/35048 is trying to acquire lock: ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm] but task is already holding lock: ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kvm_lock){+.+.}-{3:3}: __mutex_lock+0x6a/0xb40 mutex_lock_nested+0x1f/0x30 kvm_dev_ioctl+0x4fb/0xe50 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #2 (cpu_hotplug_lock){++++}-{0:0}: cpus_read_lock+0x2e/0xb0 static_key_slow_inc+0x16/0x30 kvm_lapic_set_base+0x6a/0x1c0 [kvm] kvm_set_apic_base+0x8f/0xe0 [kvm] kvm_set_msr_common+0x9ae/0xf80 [kvm] vmx_set_msr+0xa54/0xbe0 [kvm_intel] __kvm_set_msr+0xb6/0x1a0 [kvm] kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm] kvm_vcpu_ioctl+0x485/0x5b0 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #1 (&kvm->srcu){.+.+}-{0:0}: __synchronize_srcu+0x44/0x1a0 synchronize_srcu_expedited+0x21/0x30 kvm_swap_active_memslots+0x110/0x1c0 [kvm] kvm_set_memslot+0x360/0x620 [kvm] __kvm_set_memory_region+0x27b/0x300 [kvm] kvm_vm_ioctl_set_memory_region+0x43/0x60 [kvm] kvm_vm_ioctl+0x295/0x650 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #0 (&kvm->slots_lock){+.+.}-{3:3}: __lock_acquire+0x15ef/0x2e30 lock_acquire+0xe0/0x260 __mutex_lock+0x6a/0xb40 mutex_lock_nested+0x1f/0x30 set_nx_huge_pages+0x179/0x1e0 [kvm] param_attr_store+0x93/0x100 module_attr_store+0x22/0x40 sysfs_kf_write+0x81/0xb0 kernfs_fop_write_iter+0x133/0x1d0 vfs_write+0x28d/0x380 ksys_write+0x70/0xe0 __x64_sys_write+0x1f/0x30 x64_sys_call+0x281b/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e Cc: Chao Gao <chao.gao@intel.com> Fixes: 0bf5049 ("KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock") Cc: stable@vger.kernel.org Reviewed-by: Kai Huang <kai.huang@intel.com> Acked-by: Kai Huang <kai.huang@intel.com> Tested-by: Farrah Chen <farrah.chen@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-ID: <20240830043600.127750-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

On the node of an NFS client, some files saved in the mountpoint of the NFS server were copied to another location of the same NFS server. Accidentally, the nfs42_complete_copies() got a NULL-pointer dereference crash with the following syslog: [232064.838881] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232064.839360] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232066.588183] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058 [232066.588586] Mem abort info: [232066.588701] ESR = 0x0000000096000007 [232066.588862] EC = 0x25: DABT (current EL), IL = 32 bits [232066.589084] SET = 0, FnV = 0 [232066.589216] EA = 0, S1PTW = 0 [232066.589340] FSC = 0x07: level 3 translation fault [232066.589559] Data abort info: [232066.589683] ISV = 0, ISS = 0x00000007 [232066.589842] CM = 0, WnR = 0 [232066.589967] user pgtable: 64k pages, 48-bit VAs, pgdp=00002000956ff400 [232066.590231] [0000000000000058] pgd=08001100ae100003, p4d=08001100ae100003, pud=08001100ae100003, pmd=08001100b3c00003, pte=0000000000000000 [232066.590757] Internal error: Oops: 96000007 [#1] SMP [232066.590958] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm vhost_net vhost vhost_iotlb tap tun ipt_rpfilter xt_multiport ip_set_hash_ip ip_set_hash_net xfrm_interface xfrm6_tunnel tunnel4 tunnel6 esp4 ah4 wireguard libcurve25519_generic veth xt_addrtype xt_set nf_conntrack_netlink ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_bitmap_port ip_set_hash_ipport dummy ip_set ip_vs_sh ip_vs_wrr ip_vs_rr ip_vs iptable_filter sch_ingress nfnetlink_cttimeout vport_gre ip_gre ip_tunnel gre vport_geneve geneve vport_vxlan vxlan ip6_udp_tunnel udp_tunnel openvswitch nf_conncount dm_round_robin dm_service_time dm_multipath xt_nat xt_MASQUERADE nft_chain_nat nf_nat xt_mark xt_conntrack xt_comment nft_compat nft_counter nf_tables nfnetlink ocfs2 ocfs2_nodemanager ocfs2_stackglue iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_ssif nbd overlay 8021q garp mrp bonding tls rfkill sunrpc ext4 mbcache jbd2 [232066.591052] vfat fat cas_cache cas_disk ses enclosure scsi_transport_sas sg acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler ip_tables vfio_pci vfio_pci_core vfio_virqfd vfio_iommu_type1 vfio dm_mirror dm_region_hash dm_log dm_mod nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc fuse xfs libcrc32c ast drm_vram_helper qla2xxx drm_kms_helper syscopyarea crct10dif_ce sysfillrect ghash_ce sysimgblt sha2_ce fb_sys_fops cec sha256_arm64 sha1_ce drm_ttm_helper ttm nvme_fc igb sbsa_gwdt nvme_fabrics drm nvme_core i2c_algo_bit i40e scsi_transport_fc megaraid_sas aes_neon_bs [232066.596953] CPU: 6 PID: 4124696 Comm: 10.253.166.125- Kdump: loaded Not tainted 5.15.131-9.cl9_ocfs2.aarch64 #1 [232066.597356] Hardware name: Great Wall .\x93\x8e...RF6260 V5/GWMSSE2GL1T, BIOS T656FBE_V3.0.18 2024-01-06 [232066.597721] pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [232066.598034] pc : nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.598327] lr : nfs4_reclaim_open_state+0x12c/0x800 [nfsv4] [232066.598595] sp : ffff8000f568fc70 [232066.598731] x29: ffff8000f568fc70 x28: 0000000000001000 x27: ffff21003db33000 [232066.599030] x26: ffff800005521ae0 x25: ffff0100f98fa3f0 x24: 0000000000000001 [232066.599319] x23: ffff800009920008 x22: ffff21003db33040 x21: ffff21003db33050 [232066.599628] x20: ffff410172fe9e40 x19: ffff410172fe9e00 x18: 0000000000000000 [232066.599914] x17: 0000000000000000 x16: 0000000000000004 x15: 0000000000000000 [232066.600195] x14: 0000000000000000 x13: ffff800008e685a8 x12: 00000000eac0c6e6 [232066.600498] x11: 0000000000000000 x10: 0000000000000008 x9 : ffff8000054e5828 [232066.600784] x8 : 00000000ffffffbf x7 : 0000000000000001 x6 : 000000000a9eb14a [232066.601062] x5 : 0000000000000000 x4 : ffff70ff8a14a800 x3 : 0000000000000058 [232066.601348] x2 : 0000000000000001 x1 : 54dce46366daa6c6 x0 : 0000000000000000 [232066.601636] Call trace: [232066.601749] nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.601998] nfs4_do_reclaim+0x1b8/0x28c [nfsv4] [232066.602218] nfs4_state_manager+0x928/0x10f0 [nfsv4] [232066.602455] nfs4_run_state_manager+0x78/0x1b0 [nfsv4] [232066.602690] kthread+0x110/0x114 [232066.602830] ret_from_fork+0x10/0x20 [232066.602985] Code: 1400000d f9403f20 f9402e61 91016003 (f9402c00) [232066.603284] SMP: stopping secondary CPUs [232066.606936] Starting crashdump kernel... [232066.607146] Bye! Analysing the vmcore, we know that nfs4_copy_state listed by destination nfs_server->ss_copies was added by the field copies in handle_async_copy(), and we found a waiting copy process with the stack as: PID: 3511963 TASK: ffff710028b47e00 CPU: 0 COMMAND: "cp" #0 [ffff8001116ef740] __switch_to at ffff8000081b92f4 #1 [ffff8001116ef760] __schedule at ffff800008dd0650 #2 [ffff8001116ef7c0] schedule at ffff800008dd0a00 #3 [ffff8001116ef7e0] schedule_timeout at ffff800008dd6aa0 #4 [ffff8001116ef860] __wait_for_common at ffff800008dd166c #5 [ffff8001116ef8e0] wait_for_completion_interruptible at ffff800008dd1898 #6 [ffff8001116ef8f0] handle_async_copy at ffff8000055142f4 [nfsv4] #7 [ffff8001116ef970] _nfs42_proc_copy at ffff8000055147c8 [nfsv4] #8 [ffff8001116efa80] nfs42_proc_copy at ffff800005514cf0 [nfsv4] #9 [ffff8001116efc50] __nfs4_copy_file_range.constprop.0 at ffff8000054ed694 [nfsv4] The NULL-pointer dereference was due to nfs42_complete_copies() listed the nfs_server->ss_copies by the field ss_copies of nfs4_copy_state. So the nfs4_copy_state address ffff0100f98fa3f0 was offset by 0x10 and the data accessed through this pointer was also incorrect. Generally, the ordered list nfs4_state_owner->so_states indicate open(O_RDWR) or open(O_WRITE) states are reclaimed firstly by nfs4_reclaim_open_state(). When destination state reclaim is failed with NFS_STATE_RECOVERY_FAILED and copies are not deleted in nfs_server->ss_copies, the source state may be passed to the nfs42_complete_copies() process earlier, resulting in this crash scene finally. To solve this issue, we add a list_head nfs_server->ss_src_copies for a server-to-server copy specially. Fixes: 0e65a32 ("NFS: handle source server reboot") Signed-off-by: Yanjun Zhang <zhangyanjun@cestc.cn> Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

Daniel Machon says: ==================== net: sparx5: prepare for lan969x switch driver == Description: This series is the first of a multi-part series, that prepares and adds support for the new lan969x switch driver. The upstreaming efforts is split into multiple series (might change a bit as we go along): 1) Prepare the Sparx5 driver for lan969x (this series) 2) Add support lan969x (same basic features as Sparx5 provides + RGMII, excl. FDMA and VCAP) 3) Add support for lan969x FDMA 4) Add support for lan969x VCAP == Lan969x in short: The lan969x Ethernet switch family [1] provides a rich set of switching features and port configurations (up to 30 ports) from 10Mbps to 10Gbps, with support for RGMII, SGMII, QSGMII, USGMII, and USXGMII, ideal for industrial & process automation infrastructure applications, transport, grid automation, power substation automation, and ring & intra-ring topologies. The LAN969x family is hardware and software compatible and scalable supporting 46Gbps to 102Gbps switch bandwidths. == Preparing Sparx5 for lan969x: The lan969x switch chip reuses many of the IP's of the Sparx5 switch chip, therefore it has been decided to add support through the existing Sparx5 driver, in order to avoid a bunch of duplicate code. However, in order to reuse the Sparx5 switch driver, we have to introduce some mechanisms to handle the chip differences that are there. These mechanisms are: - Platform match data to contain all the differences that needs to be handled (constants, ops etc.) - Register macro indirection layer so that we can reuse the existing register macros. - Function for branching out on platform type where required. In some places we ops out functions and in other places we branch on the chip type. Exactly when we choose one over the other, is an estimate in each case. After this series is applied, the Sparx5 driver will be prepared for lan969x and still function exactly as before. == Patch breakdown: Patch #1 adds private match data Patch #2 adds register macro indirection layer Patch #3-#4 does some preparation work Patch #5-#7 adds chip constants and updates the code to use them Patch #8-#13 adds and uses ops for handling functions differently on the two platforms. Patch #14 adds and uses a macro for branching out on the chip type. Patch #15 (NEW) redefines macros for internal ports and PGID's. [1] https://www.microchip.com/en-us/product/lan9698 To: David S. Miller <davem@davemloft.net> To: Eric Dumazet <edumazet@google.com> To: Jakub Kicinski <kuba@kernel.org> To: Paolo Abeni <pabeni@redhat.com> To: Lars Povlsen <lars.povlsen@microchip.com> To: Steen Hegelund <Steen.Hegelund@microchip.com> To: horatiu.vultur@microchip.com To: jensemil.schulzostergaard@microchip.com To: UNGLinuxDriver@microchip.com To: Richard Cochran <richardcochran@gmail.com> To: horms@kernel.org To: justinstitt@google.com To: gal@nvidia.com To: aakash.r.menon@gmail.com To: jacob.e.keller@intel.com To: ast@fiberby.net Cc: netdev@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Machon <daniel.machon@microchip.com> ==================== Link: https://patch.msgid.link/20241004-b4-sparx5-lan969x-switch-driver-v2-0-d3290f581663@microchip.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>

When creating a trace_probe we would set nr_args prior to truncating the arguments to MAX_TRACE_ARGS. However, we would only initialize arguments up to the limit. This caused invalid memory access when attempting to set up probes with more than 128 fetchargs. BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 UID: 0 PID: 1769 Comm: cat Not tainted 6.11.0-rc7+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014 RIP: 0010:__set_print_fmt+0x134/0x330 Resolve the issue by applying the MAX_TRACE_ARGS limit earlier. Return an error when there are too many arguments instead of silently truncating. Link: https://lore.kernel.org/all/20240930202656.292869-1-mikel@mikelr.com/ Fixes: 035ba76 ("tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init") Signed-off-by: Mikel Rychliski <mikel@mikelr.com> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Daniel Machon says: ==================== net: sparx5: add support for lan969x switch device == Description: This series is the second of a multi-part series, that prepares and adds support for the new lan969x switch driver. The upstreaming efforts is split into multiple series (might change a bit as we go along): 1) Prepare the Sparx5 driver for lan969x (merged) --> 2) add support lan969x (same basic features as Sparx5 provides excl. FDMA and VCAP). 3) Add support for lan969x VCAP, FDMA and RGMII == Lan969x in short: The lan969x Ethernet switch family [1] provides a rich set of switching features and port configurations (up to 30 ports) from 10Mbps to 10Gbps, with support for RGMII, SGMII, QSGMII, USGMII, and USXGMII, ideal for industrial & process automation infrastructure applications, transport, grid automation, power substation automation, and ring & intra-ring topologies. The LAN969x family is hardware and software compatible and scalable supporting 46Gbps to 102Gbps switch bandwidths. == Preparing Sparx5 for lan969x: The main preparation work for lan969x has already been merged [1]. After this series is applied, lan969x will have the same functionality as Sparx5, except for VCAP and FDMA support. QoS features that requires the VCAP (e.g. PSFP, port mirroring) will obviously not work until VCAP support is added later. == Patch breakdown: Patch #1-#4 do some preparation work for lan969x Patch #5 adds new registers required by lan969x Patch #6 adds initial match data for all lan969x targets Patch #7 defines the lan969x register differences Patch #8 adds lan969x constants to match data Patch #9 adds some lan969x ops in bulk Patch #10 adds PTP function to ops Patch #11 adds lan969x_calendar.c for calculating the calendar Patch #12 makes additional use of the is_sparx5() macro to branch out in certain places. Patch #13 documents lan969x in the dt-bindings Patch #14 adds lan969x compatible string to sparx5 driver Patch #15 introduces new concept of per-target features [1] https://lore.kernel.org/netdev/20241004-b4-sparx5-lan969x-switch-driver-v2-0-d3290f581663@microchip.com/ v1: https://lore.kernel.org/20241021-sparx5-lan969x-switch-driver-2-v1-0-c8c49ef21e0f@microchip.com ==================== Link: https://patch.msgid.link/20241024-sparx5-lan969x-switch-driver-2-v2-0-a0b5fae88a0f@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

In rtl8187_stop() move the call of usb_kill_anchored_urbs() before clearing b_tx_status.queue. This change prevents callbacks from using already freed skb due to anchor was not killed before freeing such skb. BUG: kernel NULL pointer dereference, address: 0000000000000080 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Not tainted 6.15.0 #8 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 RIP: 0010:ieee80211_tx_status_irqsafe+0x21/0xc0 [mac80211] Call Trace: <IRQ> rtl8187_tx_cb+0x116/0x150 [rtl8187] __usb_hcd_giveback_urb+0x9d/0x120 usb_giveback_urb_bh+0xbb/0x140 process_one_work+0x19b/0x3c0 bh_worker+0x1a7/0x210 tasklet_action+0x10/0x30 handle_softirqs+0xf0/0x340 __irq_exit_rcu+0xcd/0xf0 common_interrupt+0x85/0xa0 </IRQ> Tested on RTL8187BvE device. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: c1db52b ("rtl8187: Use usb anchor facilities to manage urbs") Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru> Reviewed-by: Ping-Ke Shih <pkshih@realtek.com> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com> Link: https://patch.msgid.link/20250617135634.21760-1-d.dulov@aladdin.ru

Symbolize stack traces by creating a live machine. Add this functionality to dump_stack and switch dump_stack users to use it. Switch TUI to use it. Add stack traces to the child test function which can be useful to diagnose blocked code. Example output: ``` $ perf test -vv PERF_RECORD_ ... 7: PERF_RECORD_* events & perf_sample fields: 7: PERF_RECORD_* events & perf_sample fields : Running (1 active) ^C Signal (2) while running tests. Terminating tests with the same signal Internal test harness failure. Completing any started tests: : 7: PERF_RECORD_* events & perf_sample fields: ---- unexpected signal (2) ---- #0 0x55788c6210a3 in child_test_sig_handler builtin-test.c:0 #1 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0 #2 0x7fc12fe99687 in __internal_syscall_cancel cancellation.c:64 #3 0x7fc12fee5f7a in clock_nanosleep@GLIBC_2.2.5 clock_nanosleep.c:72 #4 0x7fc12fef1393 in __nanosleep nanosleep.c:26 #5 0x7fc12ff02d68 in __sleep sleep.c:55 #6 0x55788c63196b in test__PERF_RECORD perf-record.c:0 #7 0x55788c620fb0 in run_test_child builtin-test.c:0 #8 0x55788c5bd18d in start_command run-command.c:127 #9 0x55788c621ef3 in __cmd_test builtin-test.c:0 #10 0x55788c6225bf in cmd_test ??:0 #11 0x55788c5afbd0 in run_builtin perf.c:0 #12 0x55788c5afeeb in handle_internal_command perf.c:0 #13 0x55788c52b383 in main ??:0 #14 0x7fc12fe33ca8 in __libc_start_call_main libc_start_call_main.h:74 #15 0x7fc12fe33d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128 #16 0x55788c52b9d1 in _start ??:0 ---- unexpected signal (2) ---- #0 0x55788c6210a3 in child_test_sig_handler builtin-test.c:0 #1 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0 #2 0x7fc12fea3a14 in pthread_sigmask@GLIBC_2.2.5 pthread_sigmask.c:45 #3 0x7fc12fe49fd9 in __GI___sigprocmask sigprocmask.c:26 #4 0x7fc12ff2601b in __longjmp_chk longjmp.c:36 #5 0x55788c6210c0 in print_test_result.isra.0 builtin-test.c:0 #6 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0 #7 0x7fc12fe99687 in __internal_syscall_cancel cancellation.c:64 #8 0x7fc12fee5f7a in clock_nanosleep@GLIBC_2.2.5 clock_nanosleep.c:72 #9 0x7fc12fef1393 in __nanosleep nanosleep.c:26 #10 0x7fc12ff02d68 in __sleep sleep.c:55 #11 0x55788c63196b in test__PERF_RECORD perf-record.c:0 #12 0x55788c620fb0 in run_test_child builtin-test.c:0 #13 0x55788c5bd18d in start_command run-command.c:127 #14 0x55788c621ef3 in __cmd_test builtin-test.c:0 #15 0x55788c6225bf in cmd_test ??:0 #16 0x55788c5afbd0 in run_builtin perf.c:0 #17 0x55788c5afeeb in handle_internal_command perf.c:0 #18 0x55788c52b383 in main ??:0 #19 0x7fc12fe33ca8 in __libc_start_call_main libc_start_call_main.h:74 #20 0x7fc12fe33d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128 #21 0x55788c52b9d1 in _start ??:0 7: PERF_RECORD_* events & perf_sample fields : Skip (permissions) ``` Signed-off-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250624210500.2121303-1-irogers@google.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Calling perf top with branch filters enabled on Intel CPU's with branch counters logging (A.K.A LBR event logging [1]) support results in a segfault. $ perf top -e '{cpu_core/cpu-cycles/,cpu_core/event=0xc6,umask=0x3,frontend=0x11,name=frontend_retired_dsb_miss/}' -j any,counter ... Thread 27 "perf" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffafff76c0 (LWP 949003)] perf_env__find_br_cntr_info (env=0xf66dc0 <perf_env>, nr=0x0, width=0x7fffafff62c0) at util/env.c:653 653 *width = env->cpu_pmu_caps ? env->br_cntr_width : (gdb) bt #0 perf_env__find_br_cntr_info (env=0xf66dc0 <perf_env>, nr=0x0, width=0x7fffafff62c0) at util/env.c:653 #1 0x00000000005b1599 in symbol__account_br_cntr (branch=0x7fffcc3db580, evsel=0xfea2d0, offset=12, br_cntr=8) at util/annotate.c:345 #2 0x00000000005b17fb in symbol__account_cycles (addr=5658172, start=5658160, sym=0x7fffcc0ee420, cycles=539, evsel=0xfea2d0, br_cntr=8) at util/annotate.c:389 #3 0x00000000005b1976 in addr_map_symbol__account_cycles (ams=0x7fffcd7b01d0, start=0x7fffcd7b02b0, cycles=539, evsel=0xfea2d0, br_cntr=8) at util/annotate.c:422 #4 0x000000000068d57f in hist__account_cycles (bs=0x110d288, al=0x7fffafff6540, sample=0x7fffafff6760, nonany_branch_mode=false, total_cycles=0x0, evsel=0xfea2d0) at util/hist.c:2850 #5 0x0000000000446216 in hist_iter__top_callback (iter=0x7fffafff6590, al=0x7fffafff6540, single=true, arg=0x7fffffff9e00) at builtin-top.c:737 #6 0x0000000000689787 in hist_entry_iter__add (iter=0x7fffafff6590, al=0x7fffafff6540, max_stack_depth=127, arg=0x7fffffff9e00) at util/hist.c:1359 #7 0x0000000000446710 in perf_event__process_sample (tool=0x7fffffff9e00, event=0x110d250, evsel=0xfea2d0, sample=0x7fffafff6760, machine=0x108c968) at builtin-top.c:845 #8 0x0000000000447735 in deliver_event (qe=0x7fffffffa120, qevent=0x10fc200) at builtin-top.c:1211 #9 0x000000000064ccae in do_flush (oe=0x7fffffffa120, show_progress=false) at util/ordered-events.c:245 #10 0x000000000064d005 in __ordered_events__flush (oe=0x7fffffffa120, how=OE_FLUSH__TOP, timestamp=0) at util/ordered-events.c:324 #11 0x000000000064d0ef in ordered_events__flush (oe=0x7fffffffa120, how=OE_FLUSH__TOP) at util/ordered-events.c:342 #12 0x00000000004472a9 in process_thread (arg=0x7fffffff9e00) at builtin-top.c:1120 #13 0x00007ffff6e7dba8 in start_thread (arg=<optimized out>) at pthread_create.c:448 #14 0x00007ffff6f01b8c in __GI___clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78 The cause is that perf_env__find_br_cntr_info tries to access a null pointer pmu_caps in the perf_env struct. A similar issue exists for homogeneous core systems which use the cpu_pmu_caps structure. Fix this by populating cpu_pmu_caps and pmu_caps structures with values from sysfs when calling perf top with branch stack sampling enabled. [1], LBR event logging introduced here: https://lore.kernel.org/all/20231025201626.3000228-5-kan.liang@linux.intel.com/ Reviewed-by: Ian Rogers <irogers@google.com> Signed-off-by: Thomas Falcon <thomas.falcon@intel.com> Link: https://lore.kernel.org/r/20250612163659.1357950-2-thomas.falcon@intel.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Patch series "extend hung task blocker tracking to rwsems". Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> This patch (of 3): In preparation for extending blocker tracking to support rwsems, make the rwsem_owner() and is_rwsem_reader_owned() helpers globally available for determining if the blocker is a writer or one of the readers. Additionally, a stale owner pointer in a reader-owned rwsem can lead to false positives in blocker tracking when CONFIG_DETECT_HUNG_TASK_BLOCKER is enabled. To mitigate this, clear the owner field on the reader unlock path, similar to what CONFIG_DEBUG_RWSEMS does. A NULL owner is better than a stale one for diagnostics. Link: https://lkml.kernel.org/r/20250627072924.36567-1-lance.yang@linux.dev Link: https://lkml.kernel.org/r/20250627072924.36567-2-lance.yang@linux.dev Link: https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ [1] Signed-off-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [1] https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ Link: https://lkml.kernel.org/r/20250627072924.36567-3-lance.yang@linux.dev Signed-off-by: Lance Yang <lance.yang@linux.dev> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "extend hung task blocker tracking to rwsems". Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> This patch (of 3): In preparation for extending blocker tracking to support rwsems, make the rwsem_owner() and is_rwsem_reader_owned() helpers globally available for determining if the blocker is a writer or one of the readers. Additionally, a stale owner pointer in a reader-owned rwsem can lead to false positives in blocker tracking when CONFIG_DETECT_HUNG_TASK_BLOCKER is enabled. To mitigate this, clear the owner field on the reader unlock path, similar to what CONFIG_DEBUG_RWSEMS does. A NULL owner is better than a stale one for diagnostics. Link: https://lkml.kernel.org/r/20250627072924.36567-1-lance.yang@linux.dev Link: https://lkml.kernel.org/r/20250627072924.36567-2-lance.yang@linux.dev Link: https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ [1] Signed-off-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [1] https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ Link: https://lkml.kernel.org/r/20250627072924.36567-3-lance.yang@linux.dev Signed-off-by: Lance Yang <lance.yang@linux.dev> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "extend hung task blocker tracking to rwsems". Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> This patch (of 3): In preparation for extending blocker tracking to support rwsems, make the rwsem_owner() and is_rwsem_reader_owned() helpers globally available for determining if the blocker is a writer or one of the readers. Additionally, a stale owner pointer in a reader-owned rwsem can lead to false positives in blocker tracking when CONFIG_DETECT_HUNG_TASK_BLOCKER is enabled. To mitigate this, clear the owner field on the reader unlock path, similar to what CONFIG_DEBUG_RWSEMS does. A NULL owner is better than a stale one for diagnostics. Link: https://lkml.kernel.org/r/20250627072924.36567-1-lance.yang@linux.dev Link: https://lkml.kernel.org/r/20250627072924.36567-2-lance.yang@linux.dev Link: https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ [1] Signed-off-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Inspired by mutex blocker tracking[1], and having already extended it to semaphores, let's now add support for reader-writer semaphores (rwsems). The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while waiting for an rwsem, we just call hung_task_set_blocker(). The hung task detector can then query the rwsem's owner to identify the lock holder. Tracking works reliably for writers, as there can only be a single writer holding the lock, and its task struct is stored in the owner field. The main challenge lies with readers. The owner field points to only one of many concurrent readers, so we might lose track of the blocker if that specific reader unlocks, even while others remain. This is not a significant issue, however. In practice, long-lasting lock contention is almost always caused by a writer. Therefore, reliably tracking the writer is the primary goal of this patch series ;) With this change, the hung task detector can now show blocker task's info like below: [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds. [Fri Jun 27 15:21:34 2025] Tainted: G S 6.16.0-rc3 #8 [Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [Fri Jun 27 15:21:34 2025] task:cat state:D stack:0 pid:28631 tgid:28631 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? policy_nodemask+0x215/0x340 [Fri Jun 27 15:21:34 2025] ? _raw_spin_lock_irq+0x8a/0xe0 [Fri Jun 27 15:21:34 2025] ? __pfx__raw_spin_lock_irq+0x10/0x10 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_preempt_disabled+0x15/0x30 [Fri Jun 27 15:21:34 2025] rwsem_down_read_slowpath+0x55e/0xe10 [Fri Jun 27 15:21:34 2025] ? __pfx_rwsem_down_read_slowpath+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx___might_resched+0x10/0x10 [Fri Jun 27 15:21:34 2025] down_read+0xc9/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_down_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __debugfs_file_get+0x14d/0x700 [Fri Jun 27 15:21:34 2025] ? __pfx___debugfs_file_get+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? handle_pte_fault+0x52a/0x710 [Fri Jun 27 15:21:34 2025] ? selinux_file_permission+0x3a9/0x590 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_read+0x4a/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer> [Fri Jun 27 15:21:34 2025] task:cat state:S stack:0 pid:28630 tgid:28630 ppid:28501 task_flags:0x400000 flags:0x00004000 [Fri Jun 27 15:21:34 2025] Call Trace: [Fri Jun 27 15:21:34 2025] <TASK> [Fri Jun 27 15:21:34 2025] __schedule+0x7c7/0x1930 [Fri Jun 27 15:21:34 2025] ? __pfx___schedule+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __mod_timer+0x304/0xa80 [Fri Jun 27 15:21:34 2025] schedule+0x6a/0x180 [Fri Jun 27 15:21:34 2025] schedule_timeout+0xfb/0x230 [Fri Jun 27 15:21:34 2025] ? __pfx_schedule_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? __pfx_process_timeout+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? down_write+0xc4/0x140 [Fri Jun 27 15:21:34 2025] msleep_interruptible+0xbe/0x150 [Fri Jun 27 15:21:34 2025] read_dummy_rwsem_write+0x54/0x90 [Fri Jun 27 15:21:34 2025] full_proxy_read+0xff/0x1c0 [Fri Jun 27 15:21:34 2025] ? rw_verify_area+0x6d/0x410 [Fri Jun 27 15:21:34 2025] vfs_read+0x177/0xa50 [Fri Jun 27 15:21:34 2025] ? __pfx_vfs_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] ? fdget_pos+0x1cf/0x4c0 [Fri Jun 27 15:21:34 2025] ksys_read+0xfc/0x1d0 [Fri Jun 27 15:21:34 2025] ? __pfx_ksys_read+0x10/0x10 [Fri Jun 27 15:21:34 2025] do_syscall_64+0x66/0x2d0 [Fri Jun 27 15:21:34 2025] entry_SYSCALL_64_after_hwframe+0x76/0x7e [Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40 [Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40 [Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003 [Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff [Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000 [Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff [Fri Jun 27 15:21:34 2025] </TASK> [1] https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ Link: https://lkml.kernel.org/r/20250627072924.36567-3-lance.yang@linux.dev Signed-off-by: Lance Yang <lance.yang@linux.dev> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: John Stultz <jstultz@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mingzhe Yang <mingzhe.yang@ly.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Yongliang Gao <leonylgao@tencent.com> Cc: Zi Li <zi.li@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

As syzbot [1] reported as below: R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe17473450 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 Read of size 8 at addr ffff88812d962278 by task syz-executor/564 CPU: 1 PID: 564 Comm: syz-executor Tainted: G W 6.1.129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x158 lib/dump_stack.c:106 print_address_description+0x71/0x210 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:427 kasan_report+0x122/0x150 mm/kasan/report.c:531 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351 __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 __list_del_entry include/linux/list.h:134 [inline] list_del_init include/linux/list.h:206 [inline] f2fs_inode_synced+0xf7/0x2e0 fs/f2fs/super.c:1531 f2fs_update_inode+0x74/0x1c40 fs/f2fs/inode.c:585 f2fs_update_inode_page+0x137/0x170 fs/f2fs/inode.c:703 f2fs_write_inode+0x4ec/0x770 fs/f2fs/inode.c:731 write_inode fs/fs-writeback.c:1460 [inline] __writeback_single_inode+0x4a0/0xab0 fs/fs-writeback.c:1677 writeback_single_inode+0x221/0x8b0 fs/fs-writeback.c:1733 sync_inode_metadata+0xb6/0x110 fs/fs-writeback.c:2789 f2fs_sync_inode_meta+0x16d/0x2a0 fs/f2fs/checkpoint.c:1159 block_operations fs/f2fs/checkpoint.c:1269 [inline] f2fs_write_checkpoint+0xca3/0x2100 fs/f2fs/checkpoint.c:1658 kill_f2fs_super+0x231/0x390 fs/f2fs/super.c:4668 deactivate_locked_super+0x98/0x100 fs/super.c:332 deactivate_super+0xaf/0xe0 fs/super.c:363 cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1186 __cleanup_mnt+0x19/0x20 fs/namespace.c:1193 task_work_run+0x1c6/0x230 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9fb/0x2410 kernel/exit.c:871 do_group_exit+0x210/0x2d0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f28b1b8e169 Code: Unable to access opcode bytes at 0x7f28b1b8e13f. RSP: 002b:00007ffe174710a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f28b1c10879 RCX: 00007f28b1b8e169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000002 R08: 00007ffe1746ee47 R09: 00007ffe17472360 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffe17472360 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> Allocated by task 569: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4f/0x2c0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x104/0x220 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] f2fs_alloc_inode+0x2d/0x340 fs/f2fs/super.c:1419 alloc_inode fs/inode.c:261 [inline] iget_locked+0x186/0x880 fs/inode.c:1373 f2fs_iget+0x55/0x4c60 fs/f2fs/inode.c:483 f2fs_lookup+0x366/0xab0 fs/f2fs/namei.c:487 __lookup_slow+0x2a3/0x3d0 fs/namei.c:1690 lookup_slow+0x57/0x70 fs/namei.c:1707 walk_component+0x2e6/0x410 fs/namei.c:1998 lookup_last fs/namei.c:2455 [inline] path_lookupat+0x180/0x490 fs/namei.c:2479 filename_lookup+0x1f0/0x500 fs/namei.c:2508 vfs_statx+0x10b/0x660 fs/stat.c:229 vfs_fstatat fs/stat.c:267 [inline] vfs_lstat include/linux/fs.h:3424 [inline] __do_sys_newlstat fs/stat.c:423 [inline] __se_sys_newlstat+0xd5/0x350 fs/stat.c:417 __x64_sys_newlstat+0x5b/0x70 fs/stat.c:417 x64_sys_call+0x393/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:7 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 13: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:236 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free+0x12d/0x2a0 mm/slub.c:3683 f2fs_free_inode+0x24/0x30 fs/f2fs/super.c:1562 i_callback+0x4c/0x70 fs/inode.c:250 rcu_do_batch+0x503/0xb80 kernel/rcu/tree.c:2297 rcu_core+0x5a2/0xe70 kernel/rcu/tree.c:2557 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574 handle_softirqs+0x178/0x500 kernel/softirq.c:578 run_ksoftirqd+0x28/0x30 kernel/softirq.c:945 smpboot_thread_fn+0x45a/0x8c0 kernel/smpboot.c:164 kthread+0x270/0x310 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 call_rcu+0xd4/0xf70 kernel/rcu/tree.c:2845 destroy_inode fs/inode.c:316 [inline] evict+0x7da/0x870 fs/inode.c:720 iput_final fs/inode.c:1834 [inline] iput+0x62b/0x830 fs/inode.c:1860 do_unlinkat+0x356/0x540 fs/namei.c:4397 __do_sys_unlink fs/namei.c:4438 [inline] __se_sys_unlink fs/namei.c:4436 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4436 x64_sys_call+0x958/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:88 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88812d961f20 which belongs to the cache f2fs_inode_cache of size 1200 The buggy address is located 856 bytes inside of 1200-byte region [ffff88812d961f20, ffff88812d9623d0) The buggy address belongs to the physical page: page:ffffea0004b65800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12d960 head:ffffea0004b65800 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 dead000000000122 ffff88810a94c500 raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 569, tgid 568 (syz.2.16), ts 55943246141, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1d0/0x1f0 mm/page_alloc.c:2532 prep_new_page mm/page_alloc.c:2539 [inline] get_page_from_freelist+0x2e63/0x2ef0 mm/page_alloc.c:4328 __alloc_pages+0x235/0x4b0 mm/page_alloc.c:5605 alloc_slab_page include/linux/gfp.h:-1 [inline] allocate_slab mm/slub.c:1939 [inline] new_slab+0xec/0x4b0 mm/slub.c:1992 ___slab_alloc+0x6f6/0xb50 mm/slub.c:3180 __slab_alloc+0x5e/0xa0 mm/slub.c:3279 slab_alloc_node mm/slub.c:3364 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x13f/0x220 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] f2fs_alloc_inode+0x2d/0x340 fs/f2fs/super.c:1419 alloc_inode fs/inode.c:261 [inline] iget_locked+0x186/0x880 fs/inode.c:1373 f2fs_iget+0x55/0x4c60 fs/f2fs/inode.c:483 f2fs_fill_super+0x3ad7/0x6bb0 fs/f2fs/super.c:4293 mount_bdev+0x2ae/0x3e0 fs/super.c:1443 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4642 legacy_get_tree+0xea/0x190 fs/fs_context.c:632 vfs_get_tree+0x89/0x260 fs/super.c:1573 do_new_mount+0x25a/0xa20 fs/namespace.c:3056 page_owner free stack trace missing Memory state around the buggy address: ffff88812d962100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812d962180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88812d962200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88812d962280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812d962300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== [1] https://syzkaller.appspot.com/x/report.txt?x=13448368580000 This bug can be reproduced w/ the reproducer [2], once we enable CONFIG_F2FS_CHECK_FS config, the reproducer will trigger panic as below, so the direct reason of this bug is the same as the one below patch [3] fixed. kernel BUG at fs/f2fs/inode.c:857! RIP: 0010:f2fs_evict_inode+0x1204/0x1a20 Call Trace: <TASK> evict+0x32a/0x7a0 do_unlinkat+0x37b/0x5b0 __x64_sys_unlink+0xad/0x100 do_syscall_64+0x5a/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0010:f2fs_evict_inode+0x1204/0x1a20 [2] https://syzkaller.appspot.com/x/repro.c?x=17495ccc580000 [3] https://lore.kernel.org/linux-f2fs-devel/20250702120321.1080759-1-chao@kernel.org Tracepoints before panic: f2fs_unlink_enter: dev = (7,0), dir ino = 3, i_size = 4096, i_blocks = 8, name = file1 f2fs_unlink_exit: dev = (7,0), ino = 7, ret = 0 f2fs_evict_inode: dev = (7,0), ino = 7, pino = 3, i_mode = 0x81ed, i_size = 10, i_nlink = 0, i_blocks = 0, i_advise = 0x0 f2fs_truncate_node: dev = (7,0), ino = 7, nid = 8, block_address = 0x3c05 f2fs_unlink_enter: dev = (7,0), dir ino = 3, i_size = 4096, i_blocks = 8, name = file3 f2fs_unlink_exit: dev = (7,0), ino = 8, ret = 0 f2fs_evict_inode: dev = (7,0), ino = 8, pino = 3, i_mode = 0x81ed, i_size = 9000, i_nlink = 0, i_blocks = 24, i_advise = 0x4 f2fs_truncate: dev = (7,0), ino = 8, pino = 3, i_mode = 0x81ed, i_size = 0, i_nlink = 0, i_blocks = 24, i_advise = 0x4 f2fs_truncate_blocks_enter: dev = (7,0), ino = 8, i_size = 0, i_blocks = 24, start file offset = 0 f2fs_truncate_blocks_exit: dev = (7,0), ino = 8, ret = -2 The root cause is: in the fuzzed image, dnode #8 belongs to inode #7, after inode #7 eviction, dnode #8 was dropped. However there is dirent that has ino #8, so, once we unlink file3, in f2fs_evict_inode(), both f2fs_truncate() and f2fs_update_inode_page() will fail due to we can not load node #8, result in we missed to call f2fs_inode_synced() to clear inode dirty status. Let's fix this by calling f2fs_inode_synced() in error path of f2fs_evict_inode(). PS: As I verified, the reproducer [2] can trigger this bug in v6.1.129, but it failed in v6.16-rc4, this is because the testcase will stop due to other corruption has been detected by f2fs: F2FS-fs (loop0): inconsistent node block, node_type:2, nid:8, node_footer[nid:8,ino:8,ofs:0,cpver:5013063228981249506,blkaddr:15366] F2FS-fs (loop0): f2fs_lookup: inode (ino=9) has zero i_nlink Fixes: 0f18b46 ("f2fs: flush inode metadata when checkpoint is doing") Closes: https://syzkaller.appspot.com/x/report.txt?x=13448368580000 Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>