On Tue, Aug 23, 2016 at 06:55:31PM +0300, Andrey Ryabinin wrote: > Calling freeze_bdev() twice on the same block device without mounted > filesystem get_super() will return NULL, which will lead to NULL-ptr > dereference later in drop_super(). > > Check get_super() result to fix that. > > Note, that this is a purely theoretical issue. We have only 3 > freeze_bdev() callers. 2 of them are in filesystem code and used on a > device with mounted fs. The third one in lock_fs() has protection in > upper-layer code against freezing block device the second time without > thawing it first. > > Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
Looks fine, Reviewed-by: Christoph Hellwig <h...@lst.de>
