dm-verity: fix prefetch-vs-suspend race

Commit Message

Mikulas Patocka March 28, 2025, 3:17 p.m. UTC

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 <[e-mail]>
Cc: [e-mail]

---
 drivers/md/dm-verity-target.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Patch

Index: linux-2.6/drivers/md/dm-verity-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-verity-target.c	2025-03-27 15:43:09.000000000 +0100
+++ linux-2.6/drivers/md/dm-verity-target.c	2025-03-28 15:37:05.000000000 +0100
@@ -796,6 +796,13 @@  static int verity_map(struct dm_target *
 	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)
  */
@@ -1766,6 +1773,7 @@  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,