Bugzilla

Currently `SIGPROF` is an async signal on TSan codebase. TSan tries to delay the dispatch of async signals until it finds a blocking function call. It's very problematic for our case because some function calls are incorrectly marked as non-blocking: [issue 1](https://github.com/llvm/llvm-project/issues/83561), [issue 2](https://github.com/llvm/llvm-project/issues/83844).

Serge landed an [LLVM patch](https://github.com/llvm/llvm-project/pull/85188) to mark SIGPROF as sync function but I guess it'll take some time until it's released and we switch to it.  And the same applies to Rust. We can patch our own clang and rust versions in the meantime.

Currently `SIGPROF` is an async signal on TSan codebase. TSan tries to delay the dispatch of async signals until it finds a blocking function call. It's very problematic for our case because some function calls are incorrectly marked as non-blocking: [issue 1](https://github.com/llvm/llvm-project/issues/83561), [issue 2](https://github.com/llvm/llvm-project/issues/83844).

Serge landed an [LLVM patch](https://github.com/llvm/llvm-project/pull/85188) to mark SIGPROF as sync function but I guess it'll take some time until it's released and we switch to it.  And the same applies to Rust. We can patch our own clang and rust versions in the meantime.

**Edit after updating the bug**: The first patch I mentioned above is reverted by LLVM, so we need to fix it by applying https://github.com/llvm/llvm-project/pull/84162 and https://github.com/llvm/llvm-project/pull/86537 to both of our clang and rust builds.