From: Omar Sandoval <osandov@fb.com>
Date: Mon, 9 Jan 2017 19:44:12 +0000 (-0800)
Subject: virtio_blk: fix panic in initialization error path
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6bf6b0aa3da84a3d9126919a94c49c0fb7ee2fb3;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

virtio_blk: fix panic in initialization error path

If blk_mq_init_queue() returns an error, it gets assigned to
vblk->disk->queue. Then, when we call put_disk(), we end up calling
blk_put_queue() with the ERR_PTR, causing a bad dereference. Fix it by
only assigning to vblk->disk->queue on success.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 3c3b8f601469..10332c24f961 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -630,11 +630,12 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_put_disk;
 
-	q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
+	q = blk_mq_init_queue(&vblk->tag_set);
 	if (IS_ERR(q)) {
 		err = -ENOMEM;
 		goto out_free_tags;
 	}
+	vblk->disk->queue = q;
 
 	q->queuedata = vblk;