Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <65f5d26b-b0af-f9c6-e77c-e82ac969e9f9@grimberg.me>
Date:   Wed, 9 Nov 2022 04:54:18 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Subject: Re: nvme-pci: NULL pointer dereference in nvme_dev_disable() on
 linux-next
Content-Language: en-US
To:     Christoph Hellwig <hch@lst.de>, Gerd Bayer <gbayer@linux.ibm.com>
Cc:     Jens Axboe <axboe@fb.com>,
        Niklas Schnelle <schnelle@linux.ibm.com>,
        linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
        linux-nvme@lists.infradead.org
References: <fad4d2d5e24eabe1a4fcab75c5d080a6229dc88b.camel@linux.ibm.com>
 <20221108074846.GA22674@lst.de>
From:   Sagi Grimberg <sagi@grimberg.me>
In-Reply-To: <20221108074846.GA22674@lst.de>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


> Below is the minimal fix.  I'll see if I sort out the mess that is
> probe/reset failure vs ->remove a bit better, though.
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index f94b05c585cbc..577bacdcfee08 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -5160,6 +5160,8 @@ EXPORT_SYMBOL_GPL(nvme_start_freeze);
>   
>   void nvme_stop_queues(struct nvme_ctrl *ctrl)
>   {
> +	if (!ctrl->tagset)
> +		return;
>   	if (!test_and_set_bit(NVME_CTRL_STOPPED, &ctrl->flags))
>   		blk_mq_quiesce_tagset(ctrl->tagset);
>   	else
> @@ -5169,6 +5171,8 @@ EXPORT_SYMBOL_GPL(nvme_stop_queues);
>   
>   void nvme_start_queues(struct nvme_ctrl *ctrl)
>   {
> +	if (!ctrl->tagset)
> +		return;
>   	if (test_and_clear_bit(NVME_CTRL_STOPPED, &ctrl->flags))
>   		blk_mq_unquiesce_tagset(ctrl->tagset);
>   }

Can we do that in the pci driver and not here?