dm-verity: fix prefetch-vs-suspend race

There's a possible race condition in dm-verity - the prefetch work item
may race with suspend and it is possible that prefetch continues to run
while the device is suspended. Fix this by calling flush_workqueue and
dm_bufio_client_reset in the postsuspend hook.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 40448a8c74b1d054cda62b2de4ba37f4ecf7a9f2..3c427f18a04b336b95e895209c9fad39c1407cb9 100644 (file)
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -836,6 +836,13 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
        return DM_MAPIO_SUBMITTED;
 }
 
+static void verity_postsuspend(struct dm_target *ti)
+{
+       struct dm_verity *v = ti->private;
+       flush_workqueue(v->verify_wq);
+       dm_bufio_client_reset(v->bufio);
+}
+
 /*
  * Status: V (valid) or C (corruption found)
  */
@@ -1806,6 +1813,7 @@ static struct target_type verity_target = {
        .ctr            = verity_ctr,
        .dtr            = verity_dtr,
        .map            = verity_map,
+       .postsuspend    = verity_postsuspend,
        .status         = verity_status,
        .prepare_ioctl  = verity_prepare_ioctl,
        .iterate_devices = verity_iterate_devices,