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 508155b283ddcc73a967a2bc8068e67cb8cada7d..043ea1867d0f014c282a2c46529ed65c44e8ab31 100644 (file)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3490,8 +3490,10 @@ 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);