From c0d199f1617b907742bb952aa2387cf78c08afee Mon Sep 17 00:00:00 2001 From: Eliza Weisman Date: Wed, 14 Aug 2024 12:54:28 -0700 Subject: [PATCH] task: illumos/Solaris have thread-local weirdness ## Motivation In `tokio::task::local`, there's a `LocalState::assert_called_from_owner_thread` function, which checks that the caller's thread ID matches that of the thread on which the `LocalSet` was created. This assertion is disabled on FreeBSD and OpenBSD, with a comment indicating that this is because those systems have "some weirdness around thread-local destruction". If memory serves, I believe the "weirdness" was related to the order in which thread-locals are destroyed relative to each other, or something along those lines. Upon running the tests on illumos, there appears to be [a similar panic][1] in the `task_local_set_in_thread_local` due to this assertion assertion while dropping a `LocalSet` which lives in a thread-local. This leads me to believe that illumos, and presumably Solaris, also exhibit the same "weirdness". This wouldn't be too surprising, given the shared heritage of those systems. ## Solution This commit adds `target_os="illumos"` and `target_os="solaris"` to the `cfg` attribute that disables the assertion on systems determined to have weirdness. This fixes the test panicking on illumos. In the future, it might be worthwhile to look into changign the assertion to only be disabled on weirdness-having systems _while dropping the `LocalSet`_, rather than all the time. That way, we can still check other accesses. But, I wanted to make the minimum change necessary to fix it here before messing around with that. [1]: https://buildomat.eng.oxide.computer/wg/0/details/01J592RB0JR203RGGN0RYHJHMY/CHieo1Uee7qzRVyp811YBl0MvXGO3i0QA9ezPaFWj6hf6P3P/01J592RSWCNX1MCFYGW74AHVH6#S1954 --- tokio/src/task/local.rs | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/tokio/src/task/local.rs b/tokio/src/task/local.rs index 08d89c49c03..533acdb3cb9 100644 --- a/tokio/src/task/local.rs +++ b/tokio/src/task/local.rs @@ -1160,9 +1160,15 @@ impl LocalState { #[track_caller] fn assert_called_from_owner_thread(&self) { - // FreeBSD has some weirdness around thread-local destruction. + // BSDs, illumos, and Solaris have some weirdness around thread-local + // destruction. // TODO: remove this hack when thread id is cleaned up - #[cfg(not(any(target_os = "openbsd", target_os = "freebsd")))] + #[cfg(not(any( + target_os = "openbsd", + target_os = "freebsd", + target_os = "illumos", + target_os = "solaris", + )))] debug_assert!( // if we couldn't get the thread ID because we're dropping the local // data, skip the assertion --- the `Drop` impl is not going to be