commit c59ab97e9ecdee9084d2da09e5a8ceea9a396508
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> Sun Jan 04 18:28:27 2009 -0800
committer Ingo Molnar <mingo@elte.hu> Mon Jan 05 13:09:49 2009 +0100
tree 2f5cd48f324089acec80f8fb44bdc4f5de84052a
parent ea7d3fef4222cd98556a0b386598268d4dbf6670

rcu: fix rcutorture bug

Fix an rcutorture bug that prevents the shutdown notifier from ever
actually having any effect, due to the fact that kthreads ignore all
signals.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/rcutorture.c

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 3245b40..1cff28d 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -136,7 +136,7 @@
 #endif
 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 
-#define FULLSTOP_SIGNALED 1	/* Bail due to signal. */
+#define FULLSTOP_SHUTDOWN 1	/* Bail due to system shutdown/panic. */
 #define FULLSTOP_CLEANUP  2	/* Orderly shutdown. */
 static int fullstop;		/* stop generating callbacks at test end. */
 DEFINE_MUTEX(fullstop_mutex);	/* protect fullstop transitions and */
@@ -151,12 +151,10 @@
 {
 	if (fullstop)
 		return NOTIFY_DONE;
-	if (signal_pending(current)) {
-		mutex_lock(&fullstop_mutex);
-		if (!ACCESS_ONCE(fullstop))
-			fullstop = FULLSTOP_SIGNALED;
-		mutex_unlock(&fullstop_mutex);
-	}
+	mutex_lock(&fullstop_mutex);
+	if (!fullstop)
+		fullstop = FULLSTOP_SHUTDOWN;
+	mutex_unlock(&fullstop_mutex);
 	return NOTIFY_DONE;
 }
 
@@ -624,7 +622,7 @@
 		rcu_stutter_wait();
 	} while (!kthread_should_stop() && !fullstop);
 	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }
@@ -649,7 +647,7 @@
 	} while (!kthread_should_stop() && !fullstop);
 
 	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }
@@ -759,7 +757,7 @@
 	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
 	if (irqreader && cur_ops->irqcapable)
 		del_timer_sync(&t);
-	while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+	while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
 		schedule_timeout_uninterruptible(1);
 	return 0;
 }