From 8364da4751cf22201d74933d5e634176f44ed407 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fb.com>
Date: Wed, 16 May 2018 14:51:17 -0400
Subject: [PATCH] nbd: fix nbd device deletion
Git-commit: 8364da4751cf22201d74933d5e634176f44ed407
Patch-mainline: v4.18-rc1
References: bsc#1099918
This fixes a use after free bug, we shouldn't be doing disk->queue right
after we do del_gendisk(disk). Save the queue and do the cleanup after
the del_gendisk.
Fixes: c6a4759ea0c9 ("nbd: add device refcounting")
Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/block/nbd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index afbc202ca6fd..9710a0c338b0 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -173,9 +173,12 @@ static const struct device_attribute pid_attr = {
static void nbd_dev_remove(struct nbd_device *nbd)
{
struct gendisk *disk = nbd->disk;
+ struct request_queue *q;
+
if (disk) {
+ q = disk->queue;
del_gendisk(disk);
- blk_cleanup_queue(disk->queue);
+ blk_cleanup_queue(q);
blk_mq_free_tag_set(&nbd->tag_set);
disk->private_data = NULL;
put_disk(disk);
--
2.17.1