From 3c0501d28c1491ce9a4f675e9e223a8dfd9e134c Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 2 Sep 2013 15:16:36 -0400 Subject: [PATCH] in synccall, ignore the signal before any threads' signal handlers return this protects against deadlock from spurious signals (e.g. sent by another process) arriving after the controlling thread releases the other threads from the sync operation. --- src/thread/synccall.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/thread/synccall.c b/src/thread/synccall.c index c54570be..90ad1e25 100644 --- a/src/thread/synccall.c +++ b/src/thread/synccall.c @@ -71,6 +71,10 @@ void __synccall(void (*func)(void *), void *ctx) sigqueue(self->pid, SIGSYNCCALL, (union sigval){0}); while (sem_wait(&chaindone)); + sa.sa_flags = 0; + sa.sa_handler = SIG_IGN; + __libc_sigaction(SIGSYNCCALL, &sa, 0); + for (cur=head; cur; cur=cur->next) { sem_post(&cur->sem); while (sem_wait(&cur->sem2)); @@ -82,10 +86,6 @@ void __synccall(void (*func)(void *), void *ctx) sem_post(&cur->sem); } - sa.sa_flags = 0; - sa.sa_handler = SIG_IGN; - __libc_sigaction(SIGSYNCCALL, &sa, 0); - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &oldmask, 0, _NSIG/8); -- 2.25.1