X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=kernel%2Ftask_work.c;h=613b2d634af82fb6c3d4505df7159c9396e10e89;hb=98477740630f270aecf648f1d6a9dbc6027d4ff1;hp=5c0848ca1287df065303b3abbc3b4e3cb5fffa81;hpb=d7806bbd22cabc3e3b0a985cfcffa29cf156bb30;p=linux-2.6-microblaze.git

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 5c0848ca1287..613b2d634af8 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -42,7 +42,13 @@ task_work_add(struct task_struct *task, struct callback_head *work, int notify)
 		set_notify_resume(task);
 		break;
 	case TWA_SIGNAL:
-		if (lock_task_sighand(task, &flags)) {
+		/*
+		 * Only grab the sighand lock if we don't already have some
+		 * task_work pending. This pairs with the smp_store_mb()
+		 * in get_signal(), see comment there.
+		 */
+		if (!(READ_ONCE(task->jobctl) & JOBCTL_TASK_WORK) &&
+		    lock_task_sighand(task, &flags)) {
 			task->jobctl |= JOBCTL_TASK_WORK;
 			signal_wake_up(task, 0);
 			unlock_task_sighand(task, &flags);