[PATCH] nvme: avoid NULL pointer dereference in admin queue initialization error path

[Chaitanya Kulkarni]

On 4/21/22 13:55, Smith, Kyle Miller (Nimble Kernel) wrote:
> In nvme_alloc_admin_tags, the admin_q can be set to an error (typically
> -ENOMEM) if the blk_mq_init_queue call fails to set up the queue, which is
> checked for immediately after the call. However, when we return the error
> up the stack to nvme_reset_work the error takes us to
> nvme_remove_dead_ctrl -> nvme_dev_disable ->
> nvme_suspend_queue(&dev->queues[0]). Here, we only check that the admin_q
> is non-NULL, rather than not an error or NULL, and begin quiescing a queue
> that never existed, leading to bad / NULL pointer dereference.
> 
> Signed-off-by: Kyle Smith <kyles at hpe.com>
> ---
>   drivers/nvme/host/pci.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6a99ed680915..2f7510938b18 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1772,6 +1772,7 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev)
>   		dev->ctrl.admin_q = blk_mq_init_queue(&dev->admin_tagset);
>   		if (IS_ERR(dev->ctrl.admin_q)) {
>   			blk_mq_free_tag_set(&dev->admin_tagset);
> +			dev->ctrl.admin_q = NULL;
>   			return -ENOMEM;
>   		}
>   		if (!blk_get_queue(dev->ctrl.admin_q)) {
>   
> 

Please sendout a separate patch and not the reply to your original
patch with ..

-ck