[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!
GitOrigin-RevId: f01377d8ebcb1f52fe75a236cdf34f1b8b1e99fb
2 files changed
