[RH7,v2,4/4] bcache: fix cache_set_flush() NULL pointer dereference on OOM #PSBM-106785

Submitted by Andrey Ryabinin on Sept. 14, 2020, 11:33 a.m.

Details

Message ID 20200914113316.19338-4-aryabinin@virtuozzo.com
State New
Series "Series without cover letter"
Headers show

Commit Message

Andrey Ryabinin Sept. 14, 2020, 11:33 a.m.
From: Eric Wheeler <git@linux.ewheeler.net>

When bch_cache_set_alloc() fails to kzalloc the cache_set, the
asyncronous closure handling tries to dereference a cache_set that
hadn't yet been allocated inside of cache_set_flush() which is called
by __cache_set_unregister() during cleanup.  This appears to happen only
during an OOM condition on bcache_register.

Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org

https://jira.sw.ru/browse/PSBM-106785
(cherry picked from commit f8b11260a445169989d01df75d35af0f56178f95)
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
---
 drivers/md/bcache/super.c | 3 +++
 1 file changed, 3 insertions(+)

Patch hide | download patch | download mbox

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 88a008577dc0..f06212f856c6 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1295,6 +1295,9 @@  static void cache_set_flush(struct closure *cl)
 	set_bit(CACHE_SET_STOPPING_2, &c->flags);
 	wake_up(&c->alloc_wait);
 
+	if (!c)
+		closure_return(cl);
+
 	bch_cache_accounting_destroy(&c->accounting);
 
 	kobject_put(&c->internal);