From daea41651d4346a79ceb05312a8ee40fd2318f70 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Thu, 25 Apr 2019 12:07:54 -0400
Subject: [PATCH] dm delay: fix a crash when invalid device is specified
commit 81bc6d150ace6250503b825d9d0c10f7bbd24095 upstream.
When the target line contains an invalid device, delay_ctr() will call
delay_dtr() with NULL workqueue. Attempting to destroy the NULL
workqueue causes a crash.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/dm-delay.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index b4c356a21123..e789a4aae4e7 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -222,7 +222,8 @@ static void delay_dtr(struct dm_target *ti)
{
struct delay_c *dc = ti->private;
- destroy_workqueue(dc->kdelayd_wq);
+ if (dc->kdelayd_wq)
+ destroy_workqueue(dc->kdelayd_wq);
dm_put_device(ti, dc->dev_read);