X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2Fpthread_create.c;h=6e49acdc6bb77389de220d2b91e2227702b8b626;hp=6a37ee9be5c760a89923a394276406a027a45e22;hb=d674f8582ae8897715782ab9dfb5a039a9112a86;hpb=6e531f999a82cf39a951e1e9bba3cb80a6eb1464

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 6a37ee9b..6e49acdc 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -12,7 +12,7 @@ weak_alias(dummy_0, __pthread_tsd_run_dtors);
 _Noreturn void pthread_exit(void *result)
 {
 	pthread_t self = pthread_self();
-	int n;
+	sigset_t set;
 
 	self->result = result;
 
@@ -30,17 +30,30 @@ _Noreturn void pthread_exit(void *result)
 	/* Mark this thread dead before decrementing count */
 	__lock(self->killlock);
 	self->dead = 1;
-	__unlock(self->killlock);
 
 	/* Block all signals before decrementing the live thread count.
 	 * This is important to ensure that dynamically allocated TLS
 	 * is not under-allocated/over-committed, and possibly for other
 	 * reasons as well. */
-	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, 0, _NSIG/8);
+	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8);
+
+	/* Wait to unlock the kill lock, which governs functions like
+	 * pthread_kill which target a thread id, until signals have
+	 * been blocked. This precludes observation of the thread id
+	 * as a live thread (with application code running in it) after
+	 * the thread was reported dead by ESRCH being returned. */
+	__unlock(self->killlock);
 
-	do n = libc.threads_minus_1;
-	while (n && a_cas(&libc.threads_minus_1, n, n-1)!=n);
-	if (!n) exit(0);
+	/* It's impossible to determine whether this is "the last thread"
+	 * until performing the atomic decrement, since multiple threads
+	 * could exit at the same time. For the last thread, revert the
+	 * decrement and unblock signals to give the atexit handlers and
+	 * stdio cleanup code a consistent state. */
+	if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
+		libc.threads_minus_1 = 0;
+		__syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8);
+		exit(0);
+	}
 
 	if (self->detached && self->map_base) {
 		/* Detached threads must avoid the kernel clear_child_tid
@@ -190,7 +203,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
 	if (attr._a_sched) {
 		do_sched = new->startlock[0] = 1;
 		__syscall(SYS_rt_sigprocmask, SIG_BLOCK,
-			SIGALL_SET, self->sigmask, _NSIG/8);
+			SIGALL_SET, new->sigmask, _NSIG/8);
 	}
 	new->unblock_cancel = self->cancel;
 	new->canary = self->canary;