sync with FreeBSD

1 files changed, 14 insertions, 1 deletions

diff --git a/lib/libc_r/uthread/uthread_resume_np.c b/lib/libc_r/uthread/uthread_resume_np.c
index 6e211f34ece..e4be286bde6 100644
--- a/lib/libc_r/uthread/uthread_resume_np.c
+++ b/lib/libc_r/uthread/uthread_resume_np.c
@@ -29,7 +29,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $OpenBSD: uthread_resume_np.c,v 1.2 1999/01/06 05:29:26 d Exp $
+ * $OpenBSD: uthread_resume_np.c,v 1.3 1999/05/26 00:18:25 d Exp $
  */
 #include <errno.h>
 #ifdef _THREAD_SAFE
@@ -46,8 +46,21 @@ pthread_resume_np(pthread_t thread)
 	if ((ret = _find_thread(thread)) == 0) {
 		/* The thread exists. Is it suspended? */
 		if (thread->state != PS_SUSPENDED) {
+			/*
+			 * Guard against preemption by a scheduling signal.
+			 * A change of thread state modifies the waiting
+			 * and priority queues.
+			 */
+			_thread_kern_sched_defer();
+
 			/* Allow the thread to run. */
 			PTHREAD_NEW_STATE(thread,PS_RUNNING);
+
+			/*
+			 * Reenable preemption and yield if a scheduling
+			 * signal occurred while in the critical region.
+			 */
+			_thread_kern_sched_undefer();
 		}
 	}
 	return(ret);