X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2Fpthread_create.c;h=6a37ee9be5c760a89923a394276406a027a45e22;hp=6163f50910445ea7055738eb618cf4628888422b;hb=6e531f999a82cf39a951e1e9bba3cb80a6eb1464;hpb=14a835b3868e4dccece15acbff6d5da6c0e1ff17

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 6163f509..6a37ee9b 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -32,15 +32,28 @@ _Noreturn void pthread_exit(void *result)
 	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);
+
 	do n = libc.threads_minus_1;
 	while (n && a_cas(&libc.threads_minus_1, n, n-1)!=n);
 	if (!n) exit(0);
 
 	if (self->detached && self->map_base) {
-		if (self->detached == 2)
-			__syscall(SYS_set_tid_address, 0);
-		__syscall(SYS_rt_sigprocmask, SIG_BLOCK,
-			SIGALL_SET, 0, _NSIG/8);
+		/* Detached threads must avoid the kernel clear_child_tid
+		 * feature, since the virtual address will have been
+		 * unmapped and possibly already reused by a new mapping
+		 * at the time the kernel would perform the write. In
+		 * the case of threads that started out detached, the
+		 * initial clone flags are correct, but if the thread was
+		 * detached later (== 2), we need to clear it here. */
+		if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
+
+		/* The following call unmaps the thread's stack mapping
+		 * and then exits without touching the stack. */
 		__unmapself(self->map_base, self->map_size);
 	}
 
@@ -123,7 +136,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
 		size_t need = libc.tls_size + __pthread_tsd_size;
 		size = attr._a_stacksize + DEFAULT_STACK_SIZE;
 		stack = (void *)(attr._a_stackaddr & -16);
-		stack_limit = attr._a_stackaddr - size;
+		stack_limit = (void *)(attr._a_stackaddr - size);
 		/* Use application-provided stack for TLS only when
 		 * it does not take more than ~12% or 2k of the
 		 * application's stack space. */