V4L/DVB (7320): pvrusb2: Eliminate timer race during tear-down

The pvrusb2 tear-down logic was clearing two timers before stopping
its internal work queue.  That left a tiny window open where the work
queue might run after the timers are stopped, possibly starting them
again.  This could lead to dangling pointers and an oops.  Solution:
Kill the work queue first, then delete the timers.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw.c b/drivers/media/video/pvrusb2/pvrusb2-hdw.c
index f2d2677936b3..1dff2d04a5d9 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-hdw.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-hdw.c
@@ -2114,13 +2114,13 @@ void pvr2_hdw_destroy(struct pvr2_hdw *hdw)
 {
         if (!hdw) return;
         pvr2_trace(PVR2_TRACE_INIT,"pvr2_hdw_destroy: hdw=%p",hdw);
-        del_timer_sync(&hdw->quiescent_timer);
-        del_timer_sync(&hdw->encoder_wait_timer);
         if (hdw->workqueue) {
                 flush_workqueue(hdw->workqueue);
                 destroy_workqueue(hdw->workqueue);
                 hdw->workqueue = NULL;
         }
+        del_timer_sync(&hdw->quiescent_timer);
+        del_timer_sync(&hdw->encoder_wait_timer);
         if (hdw->fw_buffer) {
                 kfree(hdw->fw_buffer);
                 hdw->fw_buffer = NULL;