Mark thread_exit_state as voliatile to avoid optimizer ellision#175
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This avoids a hang when shutting down while running under -O2 or above. With -O2, the compiler sees that state is written at line 330 (CANCEL_LOCKED) and then unconditionally overwritten at line 334 (SELF_CANCEL) with no visible intervening read. It is free to elide the store at line 330. The memory location retains the stale value THREAD_EXIT_STATE_CANCEL_UNLOCKED (set at line 257 before the loop). The compiler does not account for the fact that pthread_setcancelstate on line 331 may cause the cleanup handler to fire asynchronously and read state through the pointer captured by pthread_cleanup_push. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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This avoids a hang when shutting down while running under -O2 or above. With -O2, the compiler sees that state is written at line 330 (
CANCEL_LOCKED) and then unconditionally overwritten at line 334 (SELF_CANCEL) with no visible intervening read. It is free to elide the store at line 330. The memory location retains the stale valueTHREAD_EXIT_STATE_CANCEL_UNLOCKED(set at line 257 before the loop).The compiler does not account for the fact that
pthread_setcancelstateon line 331 may cause the cleanup handler to fire asynchronously and read state through the pointer captured bypthread_cleanup_push.Fixes #174