linux: workaround to avoid deadlock inside dl_iterate_phdr in glibc #57035
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vtjnash
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profiler
backport 1.11
Extend the fix for #43578 on Darwin to also cover the same bug in Glibc (and just assume other libc have the same bug). We cannot use the same atfork trick, since the atfork implementation of this in Glibc makes this unsafe to use this after fork, just like Darwin (though for different basic concurrency mistakes in each of their respective codes). Fix #57017
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Sounds like this introduced a deadlock elsewhere: #57058. FreeBSD tests timed out also on this branch: https://buildkite.com/julialang/julia-master/builds/43702#019461a2-569c-45b2-b720-8acf560eb139 |
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Removing the backport label as this shouldn't be backported as-is given that it introduces a regression |
ararslan
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Jan 18, 2025
This is Jameson's proposed amendment to the changes made in #57035 that introduced a deadlock on FreeBSD, amusingly in service of fixing a deadlock on Linux. On Linux and (non-macOS) BSD, instead of acquiring and releasing a lock on the profiler in `jl_with_stackwalk_lock`, we're just blocking the thread from receiving the profiler's `SIGUSR2` signal at all. This should fix #57058; I don't get the deadlock locally on FreeBSD with this change, but it's AArch64 instead of x86-64 like on CI, so let's see if this also makes CI happy. If so, closes #57059. Co-authored-by: Jameson Nash <vtjnash@gmail.com>
Closed
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Re-added the backport label, should only be backported in conjunction with #57089. |
vtjnash
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Feb 3, 2025
Restores #57035, undo #57089 for non-FreeBSD. While I suggested doing this change for all platforms, I forgot that means non-FreeBSD platforms become vulnerable again to the very deadlock problems that #57035 was required to prevent. That fix seems to not be viable on FreeBSD due to known libc implementation problems on that platform. However, upon closer inspection of the questionable design implementation decisions they seem to have made here, the platform is likely not currently vulnerable to this libunwind bug in the first place: https://github.com/lattera/freebsd/blob/master/libexec/rtld-elf/rtld_lock.c#L120
vtjnash
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Feb 3, 2025
Restores #57035, undo #57089 for non-FreeBSD. While I suggested doing this change for all platforms, I forgot that means non-FreeBSD platforms become vulnerable again to the very deadlock problems that #57035 was required to prevent. That fix seems to not be viable on FreeBSD due to known libc implementation problems on that platform. However, upon closer inspection of the questionable design implementation decisions they seem to have made here, the platform is likely not currently vulnerable to this libunwind bug in the first place: https://github.com/lattera/freebsd/blob/master/libexec/rtld-elf/rtld_lock.c#L120
vtjnash
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Feb 4, 2025
Restores #57035, undo #57089 for non-FreeBSD. While I suggested doing this change for all platforms, I forgot that means non-FreeBSD platforms become vulnerable again to the very deadlock problems that #57035 was required to prevent. That fix seems to not be viable on FreeBSD due to known libc implementation problems on that platform. However, upon closer inspection of the questionable design implementation decisions they seem to have made here, the platform is likely not currently vulnerable to this libunwind bug in the first place: https://github.com/lattera/freebsd/blob/master/libexec/rtld-elf/rtld_lock.c#L120
KristofferC
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Feb 6, 2025
Restores #57035, undo #57089 for non-FreeBSD. While I suggested doing this change for all platforms, I forgot that means non-FreeBSD platforms become vulnerable again to the very deadlock problems that #57035 was required to prevent. That fix seems to not be viable on FreeBSD due to known libc implementation problems on that platform. However, upon closer inspection of the questionable design implementation decisions they seem to have made here, the platform is likely not currently vulnerable to this libunwind bug in the first place: https://github.com/lattera/freebsd/blob/master/libexec/rtld-elf/rtld_lock.c#L120 (cherry picked from commit 2f0a523)
KristofferC
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that referenced
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Feb 6, 2025
Restores #57035, undo #57089 for non-FreeBSD. While I suggested doing this change for all platforms, I forgot that means non-FreeBSD platforms become vulnerable again to the very deadlock problems that #57035 was required to prevent. That fix seems to not be viable on FreeBSD due to known libc implementation problems on that platform. However, upon closer inspection of the questionable design implementation decisions they seem to have made here, the platform is likely not currently vulnerable to this libunwind bug in the first place: https://github.com/lattera/freebsd/blob/master/libexec/rtld-elf/rtld_lock.c#L120 (cherry picked from commit 2f0a523)
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65 tasks
DilumAluthge
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Sep 5, 2025
Backported PRs: - [x] #54840 <!-- Add boundscheck in speccache_eq to avoid OOB access due to data race --> - [x] #42080 <!-- recommend explicit `using Foo: Foo, ...` in package code (was: "using considered harmful") --> - [x] #58127 <!-- [DOC] Update installation docs: /downloads/ => /install/ --> - [x] #58202 <!-- [release-1.11] malloc: use jl_get_current_task to fix null check --> - [x] #58584 <!-- Make `Ptr` values static-show w/ type-information --> - [x] #58637 <!-- Make late gc lower handle insertelement of alloca use. --> - [x] #58837 <!-- fix null comparisons for non-standard address spaces --> - [x] #57826 <!-- Add a `similar` method for `Type{<:CodeUnits}` --> - [x] #58293 <!-- fix trailing indices stackoverflow in reinterpreted array --> - [x] #58887 <!-- Pkg: Allow configuring can_fancyprint(io::IO) using IOContext --> - [x] #58937 <!-- Fix nthreadpools size in JLOptions --> - [x] #58978 <!-- Fix precompilepkgs warn loaded setting --> - [x] #58998 <!-- Bugfix: Use Base.aligned_sizeof instead of sizeof in Mmap.mmap --> - [x] #59120 <!-- Fix memory order typo in "src/julia_atomics.h" --> - [x] #59170 <!-- Clarify and enhance confusing precompile test --> Need manual backport: - [ ] #56329 <!-- loading: clean up more concurrency issues --> - [ ] #56956 <!-- Add "mea culpa" to foreign module assignment error. --> - [ ] #57035 <!-- linux: workaround to avoid deadlock inside dl_iterate_phdr in glibc --> - [ ] #57089 <!-- Block thread from receiving profile signal with stackwalk lock --> - [ ] #57249 <!-- restore non-freebsd-unix fix for profiling --> - [ ] #58011 <!-- Remove try-finally scope from `@time_imports` `@trace_compile` `@trace_dispatch` --> - [ ] #58062 <!-- remove unnecessary edge from `exp_impl` to `pow` --> - [ ] #58157 <!-- add showing a string to REPL precompile workload --> - [ ] #58209 <!-- Specialize `one` for the `SizedArray` test helper --> - [ ] #58108 <!-- Base.get_extension & Dates.format made public --> - [ ] #58356 <!-- codegen: remove readonly from abstract type calling convention --> - [ ] #58415 <!-- [REPL] more reliable extension loading --> - [ ] #58510 <!-- Don't filter `Core` methods from newly-inferred list --> - [ ] #58110 <!-- relax dispatch for the `IteratorSize` method for `Generator` --> - [ ] #58965 <!-- Fix `hygienic-scope`s in inner macro expansions --> - [ ] #58971 <!-- Fix alignment of failed precompile jobs on CI --> - [ ] #59066 <!-- build: Also pass -fno-strict-aliasing for C++ --> Contains multiple commits, manual intervention needed: - [ ] #55877 <!-- fix FileWatching designs and add workaround for a stat bug on Apple --> - [ ] #56755 <!-- docs: fix scope type of a `struct` to hard --> - [ ] #57809 <!-- Fix fptrunc Float64 -> Float16 rounding through Float32 --> - [ ] #57398 <!-- Make remaining float intrinsics require float arguments --> - [ ] #56351 <!-- Fix `--project=@script` when outside script directory --> - [ ] #57129 <!-- clarify that time_ns is monotonic --> - [ ] #58134 <!-- Note annotated string API is experimental in Julia 1.11 in HISTORY.md --> - [ ] #58401 <!-- check that hashing of types does not foreigncall (`jl_type_hash` is concrete evaluated) --> - [ ] #58435 <!-- Fix layout flags for types that have oddly sized primitive type fields --> - [ ] #58483 <!-- Fix tbaa usage when storing into heap allocated immutable structs --> - [ ] #58512 <!-- Make more types jl_static_show readably --> - [ ] #58012 <!-- Re-enable tab completion of kwargs for large method tables --> - [ ] #58683 <!-- Add 0 predecessor to entry basic block and handle it in inlining --> - [ ] #59112 <!-- Add builtin function name to add methods error --> Non-merged PRs with backport label: - [ ] #59329 <!-- aotcompile: destroy LLVM context after serializing combined module --> - [ ] #58848 <!-- Set array size only when safe to do so --> - [ ] #58535 <!-- gf.c: include const-return methods in `--trace-compile` --> - [ ] #58038 <!-- strings/cstring: `transcode`: prevent Windows sysimage invalidation --> - [ ] #57604 <!-- `@nospecialize` for `string_index_err` --> - [ ] #57366 <!-- Use ptrdiff_t sized offsets for gvars_offsets to allow large sysimages --> - [ ] #56890 <!-- Enable getting non-boxed LLVM type from Julia Type --> - [ ] #56823 <!-- Make version of opaque closure constructor in world --> - [ ] #55958 <!-- also redirect JL_STDERR etc. when redirecting to devnull --> - [ ] #55956 <!-- Make threadcall gc safe --> - [ ] #55534 <!-- Set stdlib sources as read-only during installation --> - [ ] #55499 <!-- propagate the terminal's `displaysize` to the `IOContext` used by the REPL --> - [ ] #55458 <!-- Allow for generically extracting unannotated string --> - [ ] #55457 <!-- Make AnnotateChar equality consider annotations --> - [ ] #55220 <!-- `isfile_casesensitive` fixes on Windows --> - [ ] #53957 <!-- tweak how filtering is done for what packages should be precompiled --> - [ ] #51479 <!-- prevent code loading from lookin in the versioned environment when building Julia --> - [ ] #50813 <!-- More doctests for Sockets and capitalization fix --> - [ ] #50157 <!-- improve docs for `@inbounds` and `Base.@propagate_inbounds` --> --------- Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com> Co-authored-by: adienes <51664769+adienes@users.noreply.github.com> Co-authored-by: Gabriel Baraldi <baraldigabriel@gmail.com> Co-authored-by: Keno Fischer <keno@juliacomputing.com> Co-authored-by: Simeon David Schaub <simeon@schaub.rocks> Co-authored-by: Jameson Nash <vtjnash@gmail.com> Co-authored-by: Alex Arslan <ararslan@comcast.net> Co-authored-by: Fons van der Plas <fonsvdplas@gmail.com> Co-authored-by: Ian Butterworth <i.r.butterworth@gmail.com> Co-authored-by: JonasIsensee <jonas.isensee@web.de> Co-authored-by: Curtis Vogt <curtis.vogt@gmail.com> Co-authored-by: Dilum Aluthge <dilum@aluthge.com> Co-authored-by: DilumAluthgeBot <43731525+DilumAluthgeBot@users.noreply.github.com> Co-authored-by: DilumAluthge <5619885+DilumAluthge@users.noreply.github.com>
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Extend the fix for #43578 on Darwin to also cover the same bug in Glibc (and just assume other libc have the same bug). We cannot use the same atfork trick, since the atfork implementation of this in Glibc makes this unsafe to use this after fork, just like Darwin (though for different basic concurrency mistakes in each of their respective codes).
Fix #57017