From ac30324c67d94696fdb0799e9d4fc51dc70d490b Mon Sep 17 00:00:00 2001 From: DJ Delorie Date: Tue, 3 Aug 2021 16:33:29 -0400 Subject: test-dlclose-exit-race: avoid hang on pthread_create error This test depends on the "last" function being called in a different thread than the "first" function, as "last" posts a semaphore that "first" is waiting on. However, if pthread_create fails - for example, if running in an older container before the clone3()-in-container-EPERM fixes - exit() is called in the same thread as everything else, the semaphore never gets posted, and first hangs. The fix is to pre-post that semaphore before a single-threaded exit. Reviewed-by: Arjun Shankar --- stdlib/test-dlclose-exit-race.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'stdlib/test-dlclose-exit-race.c') diff --git a/stdlib/test-dlclose-exit-race.c b/stdlib/test-dlclose-exit-race.c index b463253281..2c44efdde6 100644 --- a/stdlib/test-dlclose-exit-race.c +++ b/stdlib/test-dlclose-exit-race.c @@ -29,6 +29,7 @@ #include #include +#include #include #include #include @@ -64,6 +65,7 @@ last (void) int main (void) { + int value; void *dso; pthread_t thread; @@ -71,7 +73,17 @@ main (void) dso = xdlopen ("$ORIGIN/test-dlclose-exit-race-helper.so", RTLD_NOW|RTLD_GLOBAL); - thread = xpthread_create (NULL, exit_thread, NULL); + if ((value = pthread_create (&thread, NULL, exit_thread, NULL)) != 0) + { + /* If pthread_create fails, then exit() is called in the main + thread instead of a second thread, so the semaphore post that + would have happened in 'last' gets blocked behind the call to + first() - which is waiting on the semaphore, and thus + hangs. */ + sem_post (&order2); + errno = value; + FAIL_EXIT1 ("pthread_create: %m"); + } xdlclose (dso); xpthread_join (thread); -- cgit 1.4.1