From: Oleg Nesterov <oleg@redhat.com>
Date: Wed, 8 Jul 2015 19:42:11 +0000 (+0200)
Subject: net: pktgen: fix race between pktgen_thread_worker() and kthread_stop()
X-Git-Tag: firefly_0821_release~3679^2~93
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=f85eee641c7a3bb928a4b605db632c2e90b9574f;p=firefly-linux-kernel-4.4.55.git

net: pktgen: fix race between pktgen_thread_worker() and kthread_stop()

[ Upstream commit fecdf8be2d91e04b0a9a4f79ff06499a36f5d14f ]

pktgen_thread_worker() is obviously racy, kthread_stop() can come
between the kthread_should_stop() check and set_current_state().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Reported-by: Marcelo Leitner <mleitner@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index ebbea5371967..21a23d97e99c 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3377,8 +3377,10 @@ static int pktgen_thread_worker(void *arg)
 	pktgen_rem_thread(t);
 
 	/* Wait for kthread_stop */
-	while (!kthread_should_stop()) {
+	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);
+		if (kthread_should_stop())
+			break;
 		schedule();
 	}
 	__set_current_state(TASK_RUNNING);