commit 692d0626557451c4b557397f20b7394b612d0289
Author: Christoph Hellwig <hch@lst.de>
Date:   Tue Sep 1 11:59:41 2020 +0200

    block: fix locking in bdev_del_partition
    
    [ Upstream commit 08fc1ab6d748ab1a690fd483f41e2938984ce353 ]
    
    We need to hold the whole device bd_mutex to protect against
    other thread concurrently deleting out partition before we get
    to it, and thus causing a use after free.
    
    Fixes: cddae808aeb7 ("block: pass a hd_struct to delete_partition")
    Reported-by: syzbot+6448f3c229bc52b82f69@syzkaller.appspotmail.com
    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>

?