[all-commits] [llvm/llvm-project] f01377: [tsan] Mark `pthread_*_lock` functions as blocking...

[Nazım Can Altınova via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f01377d8ebcb1f52fe75a236cdf34f1b8b1e99fb
      https://github.com/llvm/llvm-project/commit/f01377d8ebcb1f52fe75a236cdf34f1b8b1e99fb
  Author: Nazım Can Altınova <canaltinova at gmail.com>
  Date:   2024-03-26 (Tue, 26 Mar 2024)

  Changed paths:
    M compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
    A compiler-rt/test/tsan/signal_in_mutex_lock.cpp

  Log Message:
  -----------
  [tsan] Mark `pthread_*_lock` functions as blocking (#84162)

Fixes #83561.

When a thread is blocked on a mutex and we send an async signal to that
mutex, it never arrives because tsan thinks that `pthread_mutex_lock` is
not a blocking function. This patch marks `pthread_*_lock` functions as
blocking so we can successfully deliver async signals like `SIGPROF`
when the thread is blocked on them.

See the issue also for more details. I also added a test, which is a
simplified version of the compiler explorer example I posted in the
issue.

Please let me know if you have any other ideas or things to improve!
Happy to work on them.

Also I filed #83844 which is more tricky because we don't have a libc
wrapper for `SYS_futex`. I'm not sure how to intercept this yet. Please
let me know if you have ideas on that as well. Thanks!



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