[PATCH v2] nvme: avoid NULL pointer dereference in admin queue initialization error path

[Hannes Reinecke]

On 4/22/22 16:40, 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 immediately after the call. However, when we return the error
> message 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>
> ---
> v1 -> v2:
>    - Update commit message
> 
>   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)) {
> 
Reviewed-by: Hannes Reinecke <hare at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare at suse.de                              +49 911 74053 688
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