tree 3ad740210f4672ce601d1f994b6eb8fcaa6f88ee
parent 174364f6a8979655f71b04b6492657aec3762703
author Mikulas Patocka <mpatocka@redhat.com> 1594225520 -0400
committer Mike Snitzer <snitzer@redhat.com> 1594227051 -0400

dm: use noio when sending kobject event

kobject_uevent may allocate memory and it may be called while there are dm
devices suspended. The allocation may recurse into a suspended device,
causing a deadlock. We must set the noio flag when sending a uevent.

The observed deadlock was reported here:
https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html

Reported-by: Khazhismel Kumykov <khazhy@google.com>
Reported-by: Tahsin Erdogan <tahsin@google.com>
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>