drbd: fix potential list_add corruption
If the md_sync_timer triggers a second time,
while the work queued during the first time is still pending,
this could result in list_add() of an already added item,
and corrupt the work item list.
This likely only triggered because of the erroneous
batch-dequeueing of work items fixed with
drbd: dequeue single work items in wait_for_work()
Still, skip queueing if md_sync_work is already queued.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index d831e85..732053d 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3314,7 +3314,9 @@
{
struct drbd_conf *mdev = (struct drbd_conf *) data;
- drbd_queue_work_front(&mdev->tconn->sender_work, &mdev->md_sync_work);
+ /* must not double-queue! */
+ if (list_empty(&mdev->md_sync_work.list))
+ drbd_queue_work_front(&mdev->tconn->sender_work, &mdev->md_sync_work);
}
static int w_md_sync(struct drbd_work *w, int unused)