[PATCH 4.1 122/159] net: pktgen: fix race between pktgen_thread_worker() and kthread_stop()

Greg Kroah-Hartman
2015-09-26T21:31:11Z

From: Oleg Nesterov <oleg@redhat.com>

[ 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>
---
net/core/pktgen.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3490,8 +3490,10 @@ static int pktgen_thread_worker(void *ar
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);