This is a note to let you know that I've just added the patch titled virtio_blk: fix panic in initialization error path to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: virtio_blk-fix-panic-in-initialization-error-path.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Aug 9 11:19:16 PDT 2017 From: Omar Sandoval <osandov@xxxxxx> Date: Mon, 9 Jan 2017 11:44:12 -0800 Subject: virtio_blk: fix panic in initialization error path From: Omar Sandoval <osandov@xxxxxx> [ Upstream commit 6bf6b0aa3da84a3d9126919a94c49c0fb7ee2fb3 ] 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@xxxxxx> Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/block/virtio_blk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -641,11 +641,12 @@ static int virtblk_probe(struct virtio_d 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; Patches currently in stable-queue which might be from osandov@xxxxxx are queue-4.4/virtio_blk-fix-panic-in-initialization-error-path.patch