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bpf_load_program() API is deprecated, remove perf's usage of the deprecated function. Add a __weak function declaration for libbpf version compatibility. Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Master branch: 1b8c924 |
Libbpf has deprecated the ability to keep track of object list inside libbpf, it now requires applications to track usage multiple bpf objects directly. Remove usage of bpf_object__next() API and hoist the tracking logic to perf. Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Christy Lee <christylee@fb.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Commit 82c1f13 ("selftests/bpf: Add more stats into veristat") introduced new stats, added by default in the CSV output, that were not added to parse_stat_value, used in parse_stats_csv which is used in comparison mode. Thus it broke comparison mode altogether making it fail with "Unrecognized stat #7" and EINVAL. One quirk is that PROG_TYPE and ATTACH_TYPE have been transformed to strings using libbpf_bpf_prog_type_str and libbpf_bpf_attach_type_str respectively. Since we might not want to compare those string values, we just skip the parsing in this patch. We might want to translate it back to the enum value or compare the string value directly. Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com> Tested-by: Mykyta Yatsenko<yatsenko@meta.com>
Commit 82c1f13 ("selftests/bpf: Add more stats into veristat") introduced new stats, added by default in the CSV output, that were not added to parse_stat_value, used in parse_stats_csv which is used in comparison mode. Thus it broke comparison mode altogether making it fail with "Unrecognized stat #7" and EINVAL. One quirk is that PROG_TYPE and ATTACH_TYPE have been transformed to strings using libbpf_bpf_prog_type_str and libbpf_bpf_attach_type_str respectively. Since we might not want to compare those string values, we just skip the parsing in this patch. We might want to translate it back to the enum value or compare the string value directly. Fixes: 82c1f13 ("selftests/bpf: Add more stats into veristat") Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com> Tested-by: Mykyta Yatsenko<yatsenko@meta.com> Link: https://lore.kernel.org/r/20241220152218.28405-1-mahe.tardy@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
…le_direct_reclaim() The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 #6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 #7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 #8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 #9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/20241130164346.436469-1-snishika@redhat.com Link: https://lkml.kernel.org/r/20241130161236.433747-2-snishika@redhat.com Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <snishika@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The folio refcount may be increased unexpectly through try_get_folio() by caller such as split_huge_pages. In huge_pmd_unshare(), we use refcount to check whether a pmd page table is shared. The check is incorrect if the refcount is increased by the above caller, and this can cause the page table leaked: BUG: Bad page state in process sh pfn:109324 page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x66 pfn:0x109324 flags: 0x17ffff800000000(node=0|zone=2|lastcpupid=0xfffff) page_type: f2(table) raw: 017ffff800000000 0000000000000000 0000000000000000 0000000000000000 raw: 0000000000000066 0000000000000000 00000000f2000000 0000000000000000 page dumped because: nonzero mapcount ... CPU: 31 UID: 0 PID: 7515 Comm: sh Kdump: loaded Tainted: G B 6.13.0-rc2master+ #7 Tainted: [B]=BAD_PAGE Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: show_stack+0x20/0x38 (C) dump_stack_lvl+0x80/0xf8 dump_stack+0x18/0x28 bad_page+0x8c/0x130 free_page_is_bad_report+0xa4/0xb0 free_unref_page+0x3cc/0x620 __folio_put+0xf4/0x158 split_huge_pages_all+0x1e0/0x3e8 split_huge_pages_write+0x25c/0x2d8 full_proxy_write+0x64/0xd8 vfs_write+0xcc/0x280 ksys_write+0x70/0x110 __arm64_sys_write+0x24/0x38 invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0xc8/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x34/0x128 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x190/0x198 The issue may be triggered by damon, offline_page, page_idle, etc, which will increase the refcount of page table. 1. The page table itself will be discarded after reporting the "nonzero mapcount". 2. The HugeTLB page mapped by the page table miss freeing since we treat the page table as shared and a shared page table will not be unmapped. Fix it by introducing independent PMD page table shared count. As described by comment, pt_index/pt_mm/pt_frag_refcount are used for s390 gmap, x86 pgds and powerpc, pt_share_count is used for x86/arm64/riscv pmds, so we can reuse the field as pt_share_count. Link: https://lkml.kernel.org/r/20241216071147.3984217-1-liushixin2@huawei.com Fixes: 39dde65 ("[PATCH] shared page table for hugetlb page") Signed-off-by: Liu Shixin <liushixin2@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Ken Chen <kenneth.w.chen@intel.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ido Schimmel says: ==================== net: fib_rules: Add flow label selector support In some deployments users would like to encode path information into certain bits of the IPv6 flow label, the UDP source port and the DSCP and use this information to route packets accordingly. Redirecting traffic to a routing table based on the flow label is not currently possible with Linux as FIB rules cannot match on it despite the flow label being available in the IPv6 flow key. This patchset extends FIB rules to match on the flow label with a mask. Future patches will add mask attributes to L4 ports and DSCP matches. Patches #1-#5 gradually extend FIB rules to match on the flow label. Patches #6-#7 allow user space to specify a flow label in route get requests. This is useful for both debugging and testing. Patch #8 adjusts the fib6_table_lookup tracepoint to print the flow label to the trace buffer for better observability. Patch #9 extends the FIB rule selftest with flow label test cases while utilizing the route get functionality from patch #6. ==================== Link: https://patch.msgid.link/20241216171201.274644-1-idosch@nvidia.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Daniel Machon says: ==================== net: lan969x: add RGMII support == Description: This series is the fourth 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 for lan969x (same basic features as Sparx5 provides excl. FDMA and VCAP, merged). 3) Add lan969x VCAP functionality (merged). --> 4) Add RGMII support. 5) Add FDMA support. == RGMII support: The lan969x switch device includes two RGMII port interfaces (port 28 and 29) supporting data speeds of 1 Gbps, 100 Mbps and 10 Mbps. == Patch breakdown: Patch #1 does some preparation work. Patch #2 adds new function: is_port_rgmii() to the match data ops. Patch #3 uses the is_port_rgmii() in a number of places. Patch #4 makes sure that we do not configure an RGMII device as a low-speed device, when doing a port config. Patch #5 makes sure we only return the PCS if the port mode requires it. Patch #6 adds checks for RGMII PHY modes in sparx5_verify_speeds(). Patch #7 adds registers required to configure RGMII. Patch #8 adds RGMII implementation. Patch #9 documents RGMII delays in the dt-bindings. Details are in the commit description of the individual patches v4: https://lore.kernel.org/20241213-sparx5-lan969x-switch-driver-4-v4-0-d1a72c9c4714@microchip.com v3: https://lore.kernel.org/20241118-sparx5-lan969x-switch-driver-4-v3-0-3cefee5e7e3a@microchip.com v2: https://lore.kernel.org/20241113-sparx5-lan969x-switch-driver-4-v2-0-0db98ac096d1@microchip.com v1: https://lore.kernel.org/20241106-sparx5-lan969x-switch-driver-4-v1-0-f7f7316436bd@microchip.com ==================== Link: https://patch.msgid.link/20241220-sparx5-lan969x-switch-driver-4-v5-0-fa8ba5dff732@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
libtraceevent parses and returns an array of argument fields, sometimes larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr", idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6 elements max, creating an out-of-bounds access. This runtime error is found by UBsan. The error message: $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1 builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]' #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966 #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110 #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436 #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897 #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335 #5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502 #6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351 #7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404 #8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448 #9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556 #10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360 #12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6) 0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1) = 1 Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint") Signed-off-by: Howard Chu <howardchu95@gmail.com> Link: https://lore.kernel.org/r/20250122025519.361873-1-howardchu95@gmail.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fix the suspend/resume path by ensuring the rtnl lock is held where required. Calls to ravb_open, ravb_close and wol operations must be performed under the rtnl lock to prevent conflicts with ongoing ndo operations. Without this fix, the following warning is triggered: [ 39.032969] ============================= [ 39.032983] WARNING: suspicious RCU usage [ 39.033019] ----------------------------- [ 39.033033] drivers/net/phy/phy_device.c:2004 suspicious rcu_dereference_protected() usage! ... [ 39.033597] stack backtrace: [ 39.033613] CPU: 0 UID: 0 PID: 174 Comm: python3 Not tainted 6.13.0-rc7-next-20250116-arm64-renesas-00002-g35245dfdc62c #7 [ 39.033623] Hardware name: Renesas SMARC EVK version 2 based on r9a08g045s33 (DT) [ 39.033628] Call trace: [ 39.033633] show_stack+0x14/0x1c (C) [ 39.033652] dump_stack_lvl+0xb4/0xc4 [ 39.033664] dump_stack+0x14/0x1c [ 39.033671] lockdep_rcu_suspicious+0x16c/0x22c [ 39.033682] phy_detach+0x160/0x190 [ 39.033694] phy_disconnect+0x40/0x54 [ 39.033703] ravb_close+0x6c/0x1cc [ 39.033714] ravb_suspend+0x48/0x120 [ 39.033721] dpm_run_callback+0x4c/0x14c [ 39.033731] device_suspend+0x11c/0x4dc [ 39.033740] dpm_suspend+0xdc/0x214 [ 39.033748] dpm_suspend_start+0x48/0x60 [ 39.033758] suspend_devices_and_enter+0x124/0x574 [ 39.033769] pm_suspend+0x1ac/0x274 [ 39.033778] state_store+0x88/0x124 [ 39.033788] kobj_attr_store+0x14/0x24 [ 39.033798] sysfs_kf_write+0x48/0x6c [ 39.033808] kernfs_fop_write_iter+0x118/0x1a8 [ 39.033817] vfs_write+0x27c/0x378 [ 39.033825] ksys_write+0x64/0xf4 [ 39.033833] __arm64_sys_write+0x18/0x20 [ 39.033841] invoke_syscall+0x44/0x104 [ 39.033852] el0_svc_common.constprop.0+0xb4/0xd4 [ 39.033862] do_el0_svc+0x18/0x20 [ 39.033870] el0_svc+0x3c/0xf0 [ 39.033880] el0t_64_sync_handler+0xc0/0xc4 [ 39.033888] el0t_64_sync+0x154/0x158 [ 39.041274] ravb 11c30000.ethernet eth0: Link is Down Reported-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Closes: https://lore.kernel.org/netdev/4c6419d8-c06b-495c-b987-d66c2e1ff848@tuxon.dev/ Fixes: 0184165 ("ravb: add sleep PM suspend/resume support") Signed-off-by: Kory Maincent <kory.maincent@bootlin.com> Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner: PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/20241119060842.274072-1-liuye@kylinos.cn Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <liuye@kylinos.cn> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Yang Shi <yang@os.amperecomputing.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When COWing a relocation tree path, at relocation.c:replace_path(), we can trigger a lockdep splat while we are in the btrfs_search_slot() call against the relocation root. This happens in that callchain at ctree.c:read_block_for_search() when we happen to find a child extent buffer already loaded through the fs tree with a lockdep class set to the fs tree. So when we attempt to lock that extent buffer through a relocation tree we have to reset the lockdep class to the class for a relocation tree, since a relocation tree has extent buffers that used to belong to a fs tree and may currently be already loaded (we swap extent buffers between the two trees at the end of replace_path()). However we are missing calls to btrfs_maybe_reset_lockdep_class() to reset the lockdep class at ctree.c:read_block_for_search() before we read lock an extent buffer, just like we did for btrfs_search_slot() in commit b40130b ("btrfs: fix lockdep splat with reloc root extent buffers"). So add the missing btrfs_maybe_reset_lockdep_class() calls before the attempts to read lock an extent buffer at ctree.c:read_block_for_search(). The lockdep splat was reported by syzbot and it looks like this: ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Not tainted ------------------------------------------------------ syz.0.0/5335 is trying to acquire lock: ffff8880545dbc38 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146 but task is already holding lock: ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-treloc-02/1){+.+.}-{4:4}: reacquire_held_locks+0x3eb/0x690 kernel/locking/lockdep.c:5374 __lock_release kernel/locking/lockdep.c:5563 [inline] lock_release+0x396/0xa30 kernel/locking/lockdep.c:5870 up_write+0x79/0x590 kernel/locking/rwsem.c:1629 btrfs_force_cow_block+0x14b3/0x1fd0 fs/btrfs/ctree.c:660 btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153 replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224 merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692 merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942 relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (btrfs-tree-01/1){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693 btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189 btrfs_init_new_buffer fs/btrfs/extent-tree.c:5052 [inline] btrfs_alloc_tree_block+0x41c/0x1440 fs/btrfs/extent-tree.c:5132 btrfs_force_cow_block+0x526/0x1fd0 fs/btrfs/ctree.c:573 btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153 btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4351 btrfs_insert_empty_item fs/btrfs/ctree.h:688 [inline] btrfs_insert_inode_ref+0x2bb/0xf80 fs/btrfs/inode-item.c:330 btrfs_rename_exchange fs/btrfs/inode.c:7990 [inline] btrfs_rename2+0xcb7/0x2b90 fs/btrfs/inode.c:8374 vfs_rename+0xbdb/0xf00 fs/namei.c:5067 do_renameat2+0xd94/0x13f0 fs/namei.c:5224 __do_sys_renameat2 fs/namei.c:5258 [inline] __se_sys_renameat2 fs/namei.c:5255 [inline] __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5255 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (btrfs-tree-01){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649 btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146 btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline] read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610 btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237 replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224 merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692 merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942 relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: btrfs-tree-01 --> btrfs-tree-01/1 --> btrfs-treloc-02/1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-treloc-02/1); lock(btrfs-tree-01/1); lock(btrfs-treloc-02/1); rlock(btrfs-tree-01); *** DEADLOCK *** 8 locks held by syz.0.0/5335: #0: ffff88801e3ae420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x5e/0x200 fs/namespace.c:559 #1: ffff888052c760d0 (&fs_info->reclaim_bgs_lock){+.+.}-{4:4}, at: __btrfs_balance+0x4c2/0x26b0 fs/btrfs/volumes.c:4183 #2: ffff888052c74850 (&fs_info->cleaner_mutex){+.+.}-{4:4}, at: btrfs_relocate_block_group+0x775/0xd90 fs/btrfs/relocation.c:4086 #3: ffff88801e3ae610 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xf11/0x1ad0 fs/btrfs/relocation.c:1659 #4: ffff888052c76470 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288 #5: ffff888052c76498 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288 #6: ffff8880545db878 (btrfs-tree-01/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189 #7: ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189 stack backtrace: CPU: 0 UID: 0 PID: 5335 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649 btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146 btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline] read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610 btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237 replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224 merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692 merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942 relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1ac6985d29 Code: ff ff c3 (...) RSP: 002b:00007f1ac63fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1ac6b76160 RCX: 00007f1ac6985d29 RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000007 RBP: 00007f1ac6a01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f1ac6b76160 R15: 00007fffda145a88 </TASK> Reported-by: syzbot+63913e558c084f7f8fdc@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/677b3014.050a0220.3b53b0.0064.GAE@google.com/ Fixes: 9978599 ("btrfs: reduce lock contention when eb cache miss for btree search") Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
devm_platform_profile_register() expects a pointer to the private driver data but instead an address of the pointer variable is passed due to a typo. This leads to the crashes later: BUG: unable to handle page fault for address: 00000000fe0d0044 PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 6 UID: 0 PID: 1284 Comm: tuned Tainted: G W 6.13.0+ #7 Tainted: [W]=WARN Hardware name: LENOVO 21D0/LNVNB161216, BIOS J6CN45WW 03/17/2023 RIP: 0010:__mutex_lock.constprop.0+0x6bf/0x7f0 Call Trace: <TASK> dytc_profile_set+0x4a/0x140 [ideapad_laptop] _store_and_notify+0x13/0x40 [platform_profile] class_for_each_device+0x145/0x180 platform_profile_store+0xc0/0x130 [platform_profile] kernfs_fop_write_iter+0x13e/0x1f0 vfs_write+0x290/0x450 ksys_write+0x6c/0xe0 do_syscall_64+0x82/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e Found by Linux Verification Center (linuxtesting.org). Fixes: 249c576 ("ACPI: platform_profile: Let drivers set drvdata to the class device") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Reviewed-by: Kurt Borja <kuurtb@gmail.com> Link: https://lore.kernel.org/r/20250127210202.568691-1-pchelkin@ispras.ru Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Ido Schimmel says: ==================== vxlan: Age FDB entries based on Rx traffic tl;dr - This patchset prevents VXLAN FDB entries from lingering if traffic is only forwarded to a silent host. The VXLAN driver maintains two timestamps for each FDB entry: 'used' and 'updated'. The first is refreshed by both the Rx and Tx paths and the second is refreshed upon migration. The driver ages out entries according to their 'used' time which means that an entry can linger when traffic is only forwarded to a silent host that might have migrated to a different remote. This patchset solves the problem by adjusting the above semantics and aligning them to those of the bridge driver. That is, 'used' time is refreshed by the Tx path, 'updated' time is refresh by Rx path or user space updates and entries are aged out according to their 'updated' time. Patches #1-#2 perform small changes in how the 'used' and 'updated' fields are accessed. Patches #3-#5 refresh the 'updated' time where needed. Patch #6 flips the driver to age out FDB entries according to their 'updated' time. Patch #7 removes unnecessary updates to the 'used' time. Patch #8 extends a test case to cover aging of FDB entries in the presence of Tx traffic. ==================== Link: https://patch.msgid.link/20250204145549.1216254-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Eduard Zingerman says: ==================== This patch set fixes a bug in copy_verifier_state() where the loop_entry field was not copied. This omission led to incorrect loop_entry fields remaining in env->cur_state, causing incorrect decisions about loop entry assignments in update_loop_entry(). An example of an unsafe program accepted by the verifier due to this bug can be found in patch #2. This bug can also cause an infinite loop in the verifier, see patch #5. Structure of the patch set: - Patch #1 fixes the bug but has a significant negative impact on verification performance for sched_ext programs. - Patch #3 mitigates the verification performance impact of patch #1 by avoiding clean_live_states() for states whose loop_entry is still being verified. This reduces the number of processed instructions for sched_ext programs by 28–92% in some cases. - Patches #5-6 simplify {get,update}_loop_entry() logic (and are not strictly necessary). - Patches #7–10 mitigate the memory overhead introduced by patch #1 when a program with iterator-based loop hits the 1M instruction limit. This is achieved by freeing states in env->free_list when their branches and used_as_loop_entry counts reach zero. Patches #1-4 were previously sent as a part of [1]. [1] https://lore.kernel.org/bpf/20250122120442.3536298-1-eddyz87@gmail.com/ ==================== Link: https://patch.msgid.link/20250215110411.3236773-1-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We have several places across the kernel where we want to access another task's syscall arguments, such as ptrace(2), seccomp(2), etc., by making a call to syscall_get_arguments(). This works for register arguments right away by accessing the task's `regs' member of `struct pt_regs', however for stack arguments seen with 32-bit/o32 kernels things are more complicated. Technically they ought to be obtained from the user stack with calls to an access_remote_vm(), but we have an easier way available already. So as to be able to access syscall stack arguments as regular function arguments following the MIPS calling convention we copy them over from the user stack to the kernel stack in arch/mips/kernel/scall32-o32.S, in handle_sys(), to the current stack frame's outgoing argument space at the top of the stack, which is where the handler called expects to see its incoming arguments. This area is also pointed at by the `pt_regs' pointer obtained by task_pt_regs(). Make the o32 stack argument space a proper member of `struct pt_regs' then, by renaming the existing member from `pad0' to `args' and using generated offsets to access the space. No functional change though. With the change in place the o32 kernel stack frame layout at the entry to a syscall handler invoked by handle_sys() is therefore as follows: $sp + 68 -> | ... | <- pt_regs.regs[9] +---------------------+ $sp + 64 -> | $t0 | <- pt_regs.regs[8] +---------------------+ $sp + 60 -> | $a3/argument #4 | <- pt_regs.regs[7] +---------------------+ $sp + 56 -> | $a2/argument #3 | <- pt_regs.regs[6] +---------------------+ $sp + 52 -> | $a1/argument #2 | <- pt_regs.regs[5] +---------------------+ $sp + 48 -> | $a0/argument #1 | <- pt_regs.regs[4] +---------------------+ $sp + 44 -> | $v1 | <- pt_regs.regs[3] +---------------------+ $sp + 40 -> | $v0 | <- pt_regs.regs[2] +---------------------+ $sp + 36 -> | $at | <- pt_regs.regs[1] +---------------------+ $sp + 32 -> | $zero | <- pt_regs.regs[0] +---------------------+ $sp + 28 -> | stack argument #8 | <- pt_regs.args[7] +---------------------+ $sp + 24 -> | stack argument #7 | <- pt_regs.args[6] +---------------------+ $sp + 20 -> | stack argument #6 | <- pt_regs.args[5] +---------------------+ $sp + 16 -> | stack argument #5 | <- pt_regs.args[4] +---------------------+ $sp + 12 -> | psABI space for $a3 | <- pt_regs.args[3] +---------------------+ $sp + 8 -> | psABI space for $a2 | <- pt_regs.args[2] +---------------------+ $sp + 4 -> | psABI space for $a1 | <- pt_regs.args[1] +---------------------+ $sp + 0 -> | psABI space for $a0 | <- pt_regs.args[0] +---------------------+ holding user data received and with the first 4 frame slots reserved by the psABI for the compiler to spill the incoming arguments from $a0-$a3 registers (which it sometimes does according to its needs) and the next 4 frame slots designated by the psABI for any stack function arguments that follow. This data is also available for other tasks to peek/poke at as reqired and where permitted. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This makes ptrace/get_syscall_info selftest pass on mips o32 and mips64 o32 by fixing the following two test assertions: 1. get_syscall_info test assertion on mips o32: # get_syscall_info.c:218:get_syscall_info:Expected exp_args[5] (3134521044) == info.entry.args[4] (4911432) # get_syscall_info.c:219:get_syscall_info:wait #1: entry stop mismatch 2. get_syscall_info test assertion on mips64 o32: # get_syscall_info.c:209:get_syscall_info:Expected exp_args[2] (3134324433) == info.entry.args[1] (18446744072548908753) # get_syscall_info.c:210:get_syscall_info:wait #1: entry stop mismatch The first assertion happens due to mips_get_syscall_arg() trying to access another task's context but failing to do it properly because get_user() it calls just peeks at the current task's context. It usually does not crash because the default user stack always gets assigned the same VMA, but it is pure luck which mips_get_syscall_arg() wouldn't have if e.g. the stack was switched (via setcontext(3) or however) or a non-default process's thread peeked at, and in any case irrelevant data is obtained just as observed with the test case. mips_get_syscall_arg() ought to be using access_remote_vm() instead to retrieve the other task's stack contents, but given that the data has been already obtained and saved in `struct pt_regs' it would be an overkill. The first assertion is fixed for mips o32 by using struct pt_regs.args instead of get_user() to obtain syscall arguments. This approach works due to this piece in arch/mips/kernel/scall32-o32.S: /* * Ok, copy the args from the luser stack to the kernel stack. */ .set push .set noreorder .set nomacro load_a4: user_lw(t5, 16(t0)) # argument #5 from usp load_a5: user_lw(t6, 20(t0)) # argument #6 from usp load_a6: user_lw(t7, 24(t0)) # argument #7 from usp load_a7: user_lw(t8, 28(t0)) # argument #8 from usp loads_done: sw t5, PT_ARG4(sp) # argument #5 to ksp sw t6, PT_ARG5(sp) # argument #6 to ksp sw t7, PT_ARG6(sp) # argument #7 to ksp sw t8, PT_ARG7(sp) # argument #8 to ksp .set pop .section __ex_table,"a" PTR_WD load_a4, bad_stack_a4 PTR_WD load_a5, bad_stack_a5 PTR_WD load_a6, bad_stack_a6 PTR_WD load_a7, bad_stack_a7 .previous arch/mips/kernel/scall64-o32.S has analogous code for mips64 o32 that allows fixing the issue by obtaining syscall arguments from struct pt_regs.regs[4..11] instead of the erroneous use of get_user(). The second assertion is fixed by truncating 64-bit values to 32-bit syscall arguments. Fixes: c0ff3c5 ("MIPS: Enable HAVE_ARCH_TRACEHOOK.") Signed-off-by: Dmitry V. Levin <ldv@strace.io> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
When adding LED support for mv88q222x devices the PHY private data structure was added to the mv88q211x code path, the data structure is however only allocated during mv88q222x probe. This results in a nullptr deference for mv88q2110 devices. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000001 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [0000000000000001] user address but active_mm is swapper Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc1-arm64-renesas-00342-ga3783dbf2574 #7 Hardware name: Renesas White Hawk Single board based on r8a779g2 (DT) pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : mv88q2xxx_config_init+0x28/0x84 lr : mv88q2110_config_init+0x98/0xb0 sp : ffff8000823eb9d0 x29: ffff8000823eb9d0 x28: ffff000440942000 x27: ffff80008144e400 x26: 0000000000001002 x25: 0000000000000000 x24: 0000000000000000 x23: 0000000000000009 x22: ffff8000810534f0 x21: ffff800081053550 x20: 0000000000000000 x19: ffff0004437d6800 x18: 0000000000000018 x17: 00000000000961c8 x16: ffff0006bef75ec0 x15: 0000000000000001 x14: 0000000000000001 x13: ffff000440218080 x12: 071c71c71c71c71c x11: ffff000440218080 x10: 0000000000001420 x9 : ffff8000823eb770 x8 : ffff8000823eb650 x7 : ffff8000823eb750 x6 : ffff8000823eb710 x5 : 0000000000000000 x4 : 0000000000000800 x3 : 0000000000000001 x2 : 0000000000000000 x1 : 00000000ffffffff x0 : ffff0004437d6800 Call trace: mv88q2xxx_config_init+0x28/0x84 (P) mv88q2110_config_init+0x98/0xb0 phy_init_hw+0x64/0x9c phy_attach_direct+0x118/0x320 phy_connect_direct+0x24/0x80 of_phy_connect+0x5c/0xa0 rtsn_open+0x5bc/0x78c __dev_open+0xf8/0x1fc __dev_change_flags+0x198/0x220 dev_change_flags+0x20/0x64 ip_auto_config+0x270/0xefc do_one_initcall+0xe4/0x22c kernel_init_freeable+0x2a8/0x308 kernel_init+0x20/0x130 ret_from_fork+0x10/0x20 Code: b907e404 f9432814 3100083f 540000e3 (39400680) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b SMP: stopping secondary CPUs Kernel Offset: disabled CPU features: 0x000,00000070,00801250,8200700b Memory Limit: none ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- Fix this by using a generic probe function for both mv88q211x and mv88q222x devices that allocates the PHY private data structure, while only the mv88q222x probes for LED support. Fixes: a3783db ("net: phy: marvell-88q2xxx: Add support for PHY LEDs on 88q2xxx") Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://patch.msgid.link/20250214174650.2056949-1-niklas.soderlund+renesas@ragnatech.se Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Ido Schimmel says: ==================== net: fib_rules: Add port mask support In some deployments users would like to encode path information into certain bits of the IPv6 flow label, the UDP source port and the DSCP field and use this information to route packets accordingly. Redirecting traffic to a routing table based on specific bits in the UDP source port is not currently possible. Only exact match and range are currently supported by FIB rules. This patchset extends FIB rules to match on layer 4 ports with an optional mask. The mask is not supported when matching on a range. A future patchset will add support for matching on the DSCP field with an optional mask. Patches #1-#6 gradually extend FIB rules to match on layer 4 ports with an optional mask. Patches #7-#8 add test cases for FIB rule port matching. iproute2 support can be found here [1]. [1] https://github.com/idosch/iproute2/tree/submit/fib_rule_mask_v1 ==================== Link: https://patch.msgid.link/20250217134109.311176-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Chia-Yu Chang says: ==================== AccECN protocol preparation patch series Please find the v7 v7 (03-Mar-2025) - Move 2 new patches added in v6 to the next AccECN patch series v6 (27-Dec-2024) - Avoid removing removing the potential CA_ACK_WIN_UPDATE in ack_ev_flags of patch #1 (Eric Dumazet <edumazet@google.com>) - Add reviewed-by tag in patches #2, #3, #4, #5, #6, #7, #8, #12, #14 - Foloiwng 2 new pathces are added after patch #9 (Patch that adds SKB_GSO_TCP_ACCECN) * New patch #10 to replace exisiting SKB_GSO_TCP_ECN with SKB_GSO_TCP_ACCECN in the driver to avoid CWR flag corruption * New patch #11 adds AccECN for virtio by adding new negotiation flag (VIRTIO_NET_F_HOST/GUEST_ACCECN) in feature handshake and translating Accurate ECN GSO flag between virtio_net_hdr (VIRTIO_NET_HDR_GSO_ACCECN) and skb header (SKB_GSO_TCP_ACCECN) - Add detailed changelog and comments in #13 (Eric Dumazet <edumazet@google.com>) - Move patch #14 to the next AccECN patch series (Eric Dumazet <edumazet@google.com>) v5 (5-Nov-2024) - Add helper function "tcp_flags_ntohs" to preserve last 2 bytes of TCP flags of patch #4 (Paolo Abeni <pabeni@redhat.com>) - Fix reverse X-max tree order of patches #4, #11 (Paolo Abeni <pabeni@redhat.com>) - Rename variable "delta" as "timestamp_delta" of patch #2 fo clariety - Remove patch #14 in this series (Paolo Abeni <pabeni@redhat.com>, Joel Granados <joel.granados@kernel.org>) v4 (21-Oct-2024) - Fix line length warning of patches #2, #4, #8, #10, #11, #14 - Fix spaces preferred around '|' (ctx:VxV) warning of patch #7 - Add missing CC'ed of patches #4, #12, #14 v3 (19-Oct-2024) - Fix build error in v2 v2 (18-Oct-2024) - Fix warning caused by NETIF_F_GSO_ACCECN_BIT in patch #9 (Jakub Kicinski <kuba@kernel.org>) The full patch series can be found in https://github.com/L4STeam/linux-net-next/commits/upstream_l4steam/ The Accurate ECN draft can be found in https://datatracker.ietf.org/doc/html/draft-ietf-tcpm-accurate-ecn-28 ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
perf test 11 hwmon fails on s390 with this error # ./perf test -Fv 11 --- start --- ---- end ---- 11.1: Basic parsing test : Ok --- start --- Testing 'temp_test_hwmon_event1' Using CPUID IBM,3931,704,A01,3.7,002f temp_test_hwmon_event1 -> hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/ FAILED tests/hwmon_pmu.c:189 Unexpected config for 'temp_test_hwmon_event1', 292470092988416 != 655361 ---- end ---- 11.2: Parsing without PMU name : FAILED! --- start --- Testing 'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/' FAILED tests/hwmon_pmu.c:189 Unexpected config for 'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/', 292470092988416 != 655361 ---- end ---- 11.3: Parsing with PMU name : FAILED! # The root cause is in member test_event::config which is initialized to 0xA0001 or 655361. During event parsing a long list event parsing functions are called and end up with this gdb call stack: #0 hwmon_pmu__config_term (hwm=0x168dfd0, attr=0x3ffffff5ee8, term=0x168db60, err=0x3ffffff81c8) at util/hwmon_pmu.c:623 #1 hwmon_pmu__config_terms (pmu=0x168dfd0, attr=0x3ffffff5ee8, terms=0x3ffffff5ea8, err=0x3ffffff81c8) at util/hwmon_pmu.c:662 #2 0x00000000012f870c in perf_pmu__config_terms (pmu=0x168dfd0, attr=0x3ffffff5ee8, terms=0x3ffffff5ea8, zero=false, apply_hardcoded=false, err=0x3ffffff81c8) at util/pmu.c:1519 #3 0x00000000012f88a4 in perf_pmu__config (pmu=0x168dfd0, attr=0x3ffffff5ee8, head_terms=0x3ffffff5ea8, apply_hardcoded=false, err=0x3ffffff81c8) at util/pmu.c:1545 #4 0x00000000012680c4 in parse_events_add_pmu (parse_state=0x3ffffff7fb8, list=0x168dc00, pmu=0x168dfd0, const_parsed_terms=0x3ffffff6090, auto_merge_stats=true, alternate_hw_config=10) at util/parse-events.c:1508 #5 0x00000000012684c6 in parse_events_multi_pmu_add (parse_state=0x3ffffff7fb8, event_name=0x168ec10 "temp_test_hwmon_event1", hw_config=10, const_parsed_terms=0x0, listp=0x3ffffff6230, loc_=0x3ffffff70e0) at util/parse-events.c:1592 #6 0x00000000012f0e4e in parse_events_parse (_parse_state=0x3ffffff7fb8, scanner=0x16878c0) at util/parse-events.y:293 #7 0x00000000012695a0 in parse_events__scanner (str=0x3ffffff81d8 "temp_test_hwmon_event1", input=0x0, parse_state=0x3ffffff7fb8) at util/parse-events.c:1867 #8 0x000000000126a1e8 in __parse_events (evlist=0x168b580, str=0x3ffffff81d8 "temp_test_hwmon_event1", pmu_filter=0x0, err=0x3ffffff81c8, fake_pmu=false, warn_if_reordered=true, fake_tp=false) at util/parse-events.c:2136 #9 0x00000000011e36aa in parse_events (evlist=0x168b580, str=0x3ffffff81d8 "temp_test_hwmon_event1", err=0x3ffffff81c8) at /root/linux/tools/perf/util/parse-events.h:41 #10 0x00000000011e3e64 in do_test (i=0, with_pmu=false, with_alias=false) at tests/hwmon_pmu.c:164 #11 0x00000000011e422c in test__hwmon_pmu (with_pmu=false) at tests/hwmon_pmu.c:219 #12 0x00000000011e431c in test__hwmon_pmu_without_pmu (test=0x1610368 <suite.hwmon_pmu>, subtest=1) at tests/hwmon_pmu.c:23 where the attr::config is set to value 292470092988416 or 0x10a0000000000 in line 625 of file ./util/hwmon_pmu.c: attr->config = key.type_and_num; However member key::type_and_num is defined as union and bit field: union hwmon_pmu_event_key { long type_and_num; struct { int num :16; enum hwmon_type type :8; }; }; s390 is big endian and Intel is little endian architecture. The events for the hwmon dummy pmu have num = 1 or num = 2 and type is set to HWMON_TYPE_TEMP (which is 10). On s390 this assignes member key::type_and_num the value of 0x10a0000000000 (which is 292470092988416) as shown in above trace output. Fix this and export the structure/union hwmon_pmu_event_key so the test shares the same implementation as the event parsing functions for union and bit fields. This should avoid endianess issues on all platforms. Output after: # ./perf test -F 11 11.1: Basic parsing test : Ok 11.2: Parsing without PMU name : Ok 11.3: Parsing with PMU name : Ok # Fixes: 531ee0f ("perf test: Add hwmon "PMU" test") Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Reviewed-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250131112400.568975-1-tmricht@linux.ibm.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Ian told me that there are many memory leaks in the hierarchy mode. I can easily reproduce it with the follwing command. $ make DEBUG=1 EXTRA_CFLAGS=-fsanitize=leak $ perf record --latency -g -- ./perf test -w thloop $ perf report -H --stdio ... Indirect leak of 168 byte(s) in 21 object(s) allocated from: #0 0x7f3414c16c65 in malloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:75 #1 0x55ed3602346e in map__get util/map.h:189 #2 0x55ed36024cc4 in hist_entry__init util/hist.c:476 #3 0x55ed36025208 in hist_entry__new util/hist.c:588 #4 0x55ed36027c05 in hierarchy_insert_entry util/hist.c:1587 #5 0x55ed36027e2e in hists__hierarchy_insert_entry util/hist.c:1638 #6 0x55ed36027fa4 in hists__collapse_insert_entry util/hist.c:1685 #7 0x55ed360283e8 in hists__collapse_resort util/hist.c:1776 #8 0x55ed35de0323 in report__collapse_hists /home/namhyung/project/linux/tools/perf/builtin-report.c:735 #9 0x55ed35de15b4 in __cmd_report /home/namhyung/project/linux/tools/perf/builtin-report.c:1119 #10 0x55ed35de43dc in cmd_report /home/namhyung/project/linux/tools/perf/builtin-report.c:1867 #11 0x55ed35e66767 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:351 #12 0x55ed35e66a0e in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:404 #13 0x55ed35e66b67 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:448 #14 0x55ed35e66eb0 in main /home/namhyung/project/linux/tools/perf/perf.c:556 #15 0x7f340ac33d67 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 ... $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak' 93 I found that hist_entry__delete() missed to release child entries in the hierarchy tree (hroot_{in,out}). It needs to iterate the child entries and call hist_entry__delete() recursively. After this change: $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak' 0 Reported-by: Ian Rogers <irogers@google.com> Tested-by Thomas Falcon <thomas.falcon@intel.com> Reviewed-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250307061250.320849-2-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The env.pmu_mapping can be leaked when it reads data from a pipe on AMD. For a pipe data, it reads the header data including pmu_mapping from PERF_RECORD_HEADER_FEATURE runtime. But it's already set in: perf_session__new() __perf_session__new() evlist__init_trace_event_sample_raw() evlist__has_amd_ibs() perf_env__nr_pmu_mappings() Then it'll overwrite that when it processes the HEADER_FEATURE record. Here's a report from address sanitizer. Direct leak of 2689 byte(s) in 1 object(s) allocated from: #0 0x7fed8f814596 in realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98 #1 0x5595a7d416b1 in strbuf_grow util/strbuf.c:64 #2 0x5595a7d414ef in strbuf_init util/strbuf.c:25 #3 0x5595a7d0f4b7 in perf_env__read_pmu_mappings util/env.c:362 #4 0x5595a7d12ab7 in perf_env__nr_pmu_mappings util/env.c:517 #5 0x5595a7d89d2f in evlist__has_amd_ibs util/amd-sample-raw.c:315 #6 0x5595a7d87fb2 in evlist__init_trace_event_sample_raw util/sample-raw.c:23 #7 0x5595a7d7f893 in __perf_session__new util/session.c:179 #8 0x5595a7b79572 in perf_session__new util/session.h:115 #9 0x5595a7b7e9dc in cmd_report builtin-report.c:1603 #10 0x5595a7c019eb in run_builtin perf.c:351 #11 0x5595a7c01c92 in handle_internal_command perf.c:404 #12 0x5595a7c01deb in run_argv perf.c:448 #13 0x5595a7c02134 in main perf.c:556 #14 0x7fed85833d67 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 Let's free the existing pmu_mapping data if any. Cc: Ravi Bangoria <ravi.bangoria@amd.com> Link: https://lore.kernel.org/r/20250311000416.817631-1-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently, when no active threads are running, a root user using nfsdctl command can try to remove a particular listener from the list of previously added ones, then start the server by increasing the number of threads, it leads to the following problem: [ 158.835354] refcount_t: addition on 0; use-after-free. [ 158.835603] WARNING: CPU: 2 PID: 9145 at lib/refcount.c:25 refcount_warn_saturate+0x160/0x1a0 [ 158.836017] Modules linked in: rpcrdma rdma_cm iw_cm ib_cm ib_core nfsd auth_rpcgss nfs_acl lockd grace overlay isofs uinput snd_seq_dummy snd_hrtimer nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 rfkill ip_set nf_tables qrtr sunrpc vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops uvc videobuf2_v4l2 videodev videobuf2_common snd_hda_codec_generic mc e1000e snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore sg loop dm_multipath dm_mod nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs libcrc32c crct10dif_ce ghash_ce vmwgfx sha2_ce sha256_arm64 sr_mod sha1_ce cdrom nvme drm_client_lib drm_ttm_helper ttm nvme_core drm_kms_helper nvme_auth drm fuse [ 158.840093] CPU: 2 UID: 0 PID: 9145 Comm: nfsd Kdump: loaded Tainted: G B W 6.13.0-rc6+ #7 [ 158.840624] Tainted: [B]=BAD_PAGE, [W]=WARN [ 158.840802] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS VMW201.00V.24006586.BA64.2406042154 06/04/2024 [ 158.841220] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 158.841563] pc : refcount_warn_saturate+0x160/0x1a0 [ 158.841780] lr : refcount_warn_saturate+0x160/0x1a0 [ 158.842000] sp : ffff800089be7d80 [ 158.842147] x29: ffff800089be7d80 x28: ffff00008e68c148 x27: ffff00008e68c148 [ 158.842492] x26: ffff0002e3b5c000 x25: ffff600011cd1829 x24: ffff00008653c010 [ 158.842832] x23: ffff00008653c000 x22: 1fffe00011cd1829 x21: ffff00008653c028 [ 158.843175] x20: 0000000000000002 x19: ffff00008653c010 x18: 0000000000000000 [ 158.843505] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 158.843836] x14: 0000000000000000 x13: 0000000000000001 x12: ffff600050a26493 [ 158.844143] x11: 1fffe00050a26492 x10: ffff600050a26492 x9 : dfff800000000000 [ 158.844475] x8 : 00009fffaf5d9b6e x7 : ffff000285132493 x6 : 0000000000000001 [ 158.844823] x5 : ffff000285132490 x4 : ffff600050a26493 x3 : ffff8000805e72bc [ 158.845174] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000098588000 [ 158.845528] Call trace: [ 158.845658] refcount_warn_saturate+0x160/0x1a0 (P) [ 158.845894] svc_recv+0x58c/0x680 [sunrpc] [ 158.846183] nfsd+0x1fc/0x348 [nfsd] [ 158.846390] kthread+0x274/0x2f8 [ 158.846546] ret_from_fork+0x10/0x20 [ 158.846714] ---[ end trace 0000000000000000 ]--- nfsd_nl_listener_set_doit() would manipulate the list of transports of server's sv_permsocks and close the specified listener but the other list of transports (server's sp_xprts list) would not be changed leading to the problem above. Instead, determined if the nfsdctl is trying to remove a listener, in which case, delete all the existing listener transports and re-create all-but-the-removed ones. Fixes: 16a4711 ("NFSD: add listener-{set,get} netlink command") Signed-off-by: Olga Kornievskaia <okorniev@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
…ge_order() Patch series "mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT", v3. Let's add an "easy" way to decide -- without false positives, without page-mapcounts and without page table/rmap scanning -- whether a large folio is "certainly mapped exclusively" into a single MM, or whether it "maybe mapped shared" into multiple MMs. Use that information to implement Copy-on-Write reuse, to convert folio_likely_mapped_shared() to folio_maybe_mapped_share(), and to introduce a kernel config option that lets us not use+maintain per-page mapcounts in large folios anymore. The bigger picture was presented at LSF/MM [1]. This series is effectively a follow-up on my early work [2], which implemented a more precise, but also more complicated, way to identify whether a large folio is "mapped shared" into multiple MMs or "mapped exclusively" into a single MM. 1 Patch Organization ==================== Patch #1 -> #6: make more room in order-1 folios, so we have two "unsigned long" available for our purposes Patch #7 -> #11: preparations Patch #12: MM owner tracking for large folios Patch #13: COW reuse for PTE-mapped anon THP Patch #14: folio_maybe_mapped_shared() Patch #15 -> #20: introduce and implement CONFIG_NO_PAGE_MAPCOUNT 2 MM owner tracking =================== We assign each MM a unique ID ("MM ID"), to be able to squeeze more information in our folios. On 32bit we use 15-bit IDs, on 64bit we use 31-bit IDs. For each large folios, we now store two MM-ID+mapcount ("slot") combinations: * mm0_id + mm0_mapcount * mm1_id + mm1_mapcount On 32bit, we use a 16-bit per-MM mapcount, on 64bit an ordinary 32bit mapcount. This way, we require 2x "unsigned long" on 32bit and 64bit for both slots. Paired with the large mapcount, we can reliably identify whether one of these MMs is the current owner (-> owns all mappings) or even holds all folio references (-> owns all mappings, and all references are from mappings). As long as only two MMs map folio pages at a time, we can reliably and precisely identify whether a large folio is "mapped shared" or "mapped exclusively". Any additional MM that starts mapping the folio while there are no free slots becomes an "untracked MM". If one such "untracked MM" is the last one mapping a folio exclusively, we will not detect the folio as "mapped exclusively" but instead as "maybe mapped shared". (exception: only a single mapping remains) So that's where the approach gets imprecise. For now, we use a bit-spinlock to sync the large mapcount + slots, and make sure we do keep the machinery fast, to not degrade (un)map performance drastically: for example, we make sure to only use a single atomic (when grabbing the bit-spinlock), like we would already perform when updating the large mapcount. 3 CONFIG_NO_PAGE_MAPCOUNT ========================= patch #15 -> #20 spell out and document what exactly is affected when not maintaining the per-page mapcounts in large folios anymore. Most importantly, as we cannot maintain folio->_nr_pages_mapped anymore when (un)mapping pages, we'll account a complete folio as mapped if a single page is mapped. In addition, we'll not detect partially mapped anonymous folios as such in all cases yet. Likely less relevant changes include that we might now under-estimate the USS (Unique Set Size) of a process, but never over-estimate it. The goal is to make CONFIG_NO_PAGE_MAPCOUNT the default at some point, to then slowly make it the only option, as we learn about real-life impacts and possible ways to mitigate them. 4 Performance ============= Detailed performance numbers were included in v1 [3], and not that much changed between v1 and v2. I did plenty of measurements on different systems in the meantime, that all revealed slightly different results. The pte-mapped-folio micro-benchmarks [4] are fairly sensitive to code layout changes on some systems. Especially the fork() benchmark started being more-shaky-than-before on recent kernels for some reason. In summary, with my micro-benchmarks: * Small folios are not impacted. * CoW performance seems to be mostly unchanged across all folios sizes. * CoW reuse performance of large folios now matches CoW reuse performance of small folios, because we now actually implement the CoW reuse optimization. On an Intel Xeon Silver 4210R I measured a ~65% reduction in runtime, on an arm64 system I measured ~54% reduction. * munmap() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw double-digit % reduction (up to ~30% on an Intel Xeon Silver 4210R and up to ~70% on an AmpereOne A192-32X) with larger folios. The larger the folios, the larger the performance improvement. * munmao() performance very slightly (couple percent) degrades without CONFIG_NO_PAGE_MAPCOUNT for smaller folios. For larger folios, there seems to be no change at all. * fork() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw double-digit % reduction (up to ~20% on an Intel Xeon Silver 4210R and up to ~10% on an AmpereOne A192-32X) with larger folios. The larger the folios, the larger the performance improvement. * While fork() performance without CONFIG_NO_PAGE_MAPCOUNT seems to be almost unchanged on some systems, I saw some degradation for smaller folios on the AmpereOne A192-32X. I did not investigate the details yet, but I suspect code layout changes or suboptimal code placement / inlining. I'm not to worried about the fork() micro-benchmarks for smaller folios given how shaky the results are lately and by how much we improved fork() performance recently. I also ran case-anon-cow-rand and case-anon-cow-seq part of vm-scalability, to assess the scalability and the impact of the bit-spinlock. My measurements on a two 2-socket 10-core Intel Xeon Silver 4210R CPU revealed no significant changes. Similarly, running these benchmarks with 2 MiB THPs enabled on the AmpereOne A192-32X with 192 cores, I got < 1% difference with < 1% stdev, which is nice. So far, I did not get my hands on a similarly large system with multiple sockets. I found no other fitting scalability benchmarks that seem to really hammer on concurrent mapping/unmapping of large folio pages like case-anon-cow-seq does. 5 Concerns ========== 5.1 Bit spinlock ---------------- I'm not quite happy about the bit-spinlock, but so far it does not seem to affect scalability in my measurements. If it ever becomes a problem we could either investigate improving the locking, or simply stopping the MM tracking once there are "too many mappings" and simply assume that the folio is "mapped shared" until it was freed. This would be similar (but slightly different) to the "0,1,2,stopped" counting idea Willy had at some point. Adding that logic to "stop tracking" adds more code to the hot path, so I avoided that for now. 5.2 folio_maybe_mapped_shared() ------------------------------- I documented the change from folio_likely_mapped_shared() to folio_maybe_mapped_shared() quite extensively. If we run into surprises, I have some ideas on how to resolve them. For now, I think we should be fine. 5.3 Added code to map/unmap hot path ------------------------------------ So far, it looks like the added code on the rmap hot path does not really seem to matter much in the bigger picture. I'd like to further reduce it (and possibly improve fork() performance further), but I don't easily see how right now. Well, and I am out of puff 🙂 Having that said, alternatives I considered (e.g., per-MM per-folio mapcount) would add a lot more overhead to these hot paths. 6 Future Work ============= 6.1 Large mapcount ------------------ It would be very handy if the large mapcount would count how often folio pages are actually mapped into page tables: a PMD on x86-64 would count 512 times. Calculating the average per-page mapcount will be easy, and remapping (PMD->PTE) folios would get even faster. That would also remove the need for the entire mapcount (except for PMD-sized folios for memory statistics reasons ...), and allow for mapping folios larger than PMDs (e.g., 4 MiB) easily. We likely would also have to take the same number of folio references to make our folio_mapcount() == folio_ref_count() work, and we'd want to be able to avoid mapcount+refcount overflows: this could already become an issue with pte-mapped PUD-sized folios (fsdax). One approach we discussed in the THP cabal meeting is (1) extending the mapcount for large folios to 64bit (at least on 64bit systems) and (2) keeping the refcount at 32bit, but (3) having exactly one reference if the the mapcount != 0. It should be doable, but there are some corner cases to consider on the unmap path; it is something that I will be looking into next. 6.2 hugetlb ----------- I'd love to make use of the same tracking also for hugetlb. The real problem is PMD table sharing: getting a page mapped by MM X and unmapped by MM Y will not work. With mshare, that problem should not exist (all mapping/unmapping will be routed through the mshare MM). [1] https://lwn.net/Articles/974223/ [2] https://lore.kernel.org/linux-mm/a9922f58-8129-4f15-b160-e0ace581bcbe@redhat.com/T/ [3] https://lkml.kernel.org/r/20240829165627.2256514-1-david@redhat.com [4] https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/pte-mapped-folio-benchmarks.c This patch (of 20): Let's factor it out into a simple helper function. This helper will also come in handy when working with code where we know that our folio is large. Maybe in the future we'll have the order readily available for small and large folios; in that case, folio_large_order() would simply translate to folio_order(). Link: https://lkml.kernel.org/r/20250303163014.1128035-1-david@redhat.com Link: https://lkml.kernel.org/r/20250303163014.1128035-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lance Yang <ioworker0@gmail.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirks^H^Hski <luto@kernel.org> Cc: Borislav Betkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: tejun heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a bio with REQ_PREFLUSH is submitted to dm, __send_empty_flush() generates a flush_bio with REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC, which causes the flush_bio to be throttled by wbt_wait(). An example from v5.4, similar problem also exists in upstream: crash> bt 2091206 PID: 2091206 TASK: ffff2050df92a300 CPU: 109 COMMAND: "kworker/u260:0" #0 [ffff800084a2f7f0] __switch_to at ffff80004008aeb8 #1 [ffff800084a2f820] __schedule at ffff800040bfa0c4 #2 [ffff800084a2f880] schedule at ffff800040bfa4b4 #3 [ffff800084a2f8a0] io_schedule at ffff800040bfa9c4 #4 [ffff800084a2f8c0] rq_qos_wait at ffff8000405925bc #5 [ffff800084a2f940] wbt_wait at ffff8000405bb3a0 #6 [ffff800084a2f9a0] __rq_qos_throttle at ffff800040592254 #7 [ffff800084a2f9c0] blk_mq_make_request at ffff80004057cf38 #8 [ffff800084a2fa60] generic_make_request at ffff800040570138 #9 [ffff800084a2fae0] submit_bio at ffff8000405703b4 #10 [ffff800084a2fb50] xlog_write_iclog at ffff800001280834 [xfs] #11 [ffff800084a2fbb0] xlog_sync at ffff800001280c3c [xfs] #12 [ffff800084a2fbf0] xlog_state_release_iclog at ffff800001280df4 [xfs] #13 [ffff800084a2fc10] xlog_write at ffff80000128203c [xfs] #14 [ffff800084a2fcd0] xlog_cil_push at ffff8000012846dc [xfs] #15 [ffff800084a2fda0] xlog_cil_push_work at ffff800001284a2c [xfs] #16 [ffff800084a2fdb0] process_one_work at ffff800040111d08 #17 [ffff800084a2fe00] worker_thread at ffff8000401121cc #18 [ffff800084a2fe70] kthread at ffff800040118de4 After commit 2def284 ("xfs: don't allow log IO to be throttled"), the metadata submitted by xlog_write_iclog() should not be throttled. But due to the existence of the dm layer, throttling flush_bio indirectly causes the metadata bio to be throttled. Fix this by conditionally adding REQ_IDLE to flush_bio.bi_opf, which makes wbt_should_throttle() return false to avoid wbt_wait(). Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Tianxiang Peng <txpeng@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
As reported by CVE-2025-29481 [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The CVE report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Put the above condition back to bpf_object__init_prog to make sure that the program start is also within the bounds of the section to avoid the potential buffer overflow. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037@qq.com> Cc: stable@vger.kernel.org Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://www.cve.org/CVERecord?id=CVE-2025-29481 Signed-off-by: Viktor Malik <vmalik@redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
As reported by CVE-2025-29481 [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The CVE report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Put the above condition back to bpf_object__init_prog to make sure that the program start is also within the bounds of the section to avoid the potential buffer overflow. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037@qq.com> Cc: stable@vger.kernel.org Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://www.cve.org/CVERecord?id=CVE-2025-29481 Signed-off-by: Viktor Malik <vmalik@redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037@qq.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Signed-off-by: Viktor Malik <vmalik@redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037@qq.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Signed-off-by: Viktor Malik <vmalik@redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Reported-by: lmarch2 <2524158037@qq.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Signed-off-by: Viktor Malik <vmalik@redhat.com> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Reported-by: lmarch2 <2524158037@qq.com> Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com
Pull request for series with
subject: perf: stop using deprecated bpf APIs
version: 6
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=613742