Re: [PATCH] nvme-tcp: fix crash triggered with a dataless request submission

From: Yi Zhang <yi.zhang@redhat.com>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Sagi Grimberg <sagi@grimberg.me>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH] nvme-tcp: fix crash triggered with a dataless request submission
Date: Thu, 11 Feb 2021 12:04:52 +0800	[thread overview]
Message-ID: <3d3efa8d-5e77-6cdf-88b4-a225fab36ffc@redhat.com> (raw)
In-Reply-To: <BYAPR04MB49650F2CB6A009986E0DC517868D9@BYAPR04MB4965.namprd04.prod.outlook.com>


On 2/11/21 6:16 AM, Chaitanya Kulkarni wrote:
> On 2/10/21 2:10 PM, Sagi Grimberg wrote:
>> write-zeros has a bio, but does not have any data buffers associated
>> with it. Hence should not initialize the request iter for it (which
>> attempts to reference the bi_io_vec (and crash).
>> --
>>   run blktests nvme/012 at 2021-02-05 21:53:34
>>   BUG: kernel NULL pointer dereference, address: 0000000000000008
>>   #PF: supervisor read access in kernel mode
>>   #PF: error_code(0x0000) - not-present page
>>   PGD 0 P4D 0
>>   Oops: 0000 [#1] SMP NOPTI
>>   CPU: 15 PID: 12069 Comm: kworker/15:2H Tainted: G S        I       5.11.0-rc6+ #1
>>   Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.10.0 11/12/2020
>>   Workqueue: kblockd blk_mq_run_work_fn
>>   RIP: 0010:nvme_tcp_init_iter+0x7d/0xd0 [nvme_tcp]
>>   RSP: 0018:ffffbd084447bd18 EFLAGS: 00010246
>>   RAX: 0000000000000000 RBX: ffffa0bba9f3ce80 RCX: 0000000000000000
>>   RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000002000000
>>   RBP: ffffa0ba8ac6fec0 R08: 0000000002000000 R09: 0000000000000000
>>   R10: 0000000002800809 R11: 0000000000000000 R12: 0000000000000000
>>   R13: ffffa0bba9f3cf90 R14: 0000000000000000 R15: 0000000000000000
>>   FS:  0000000000000000(0000) GS:ffffa0c9ff9c0000(0000) knlGS:0000000000000000
>>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>   CR2: 0000000000000008 CR3: 00000001c9c6c005 CR4: 00000000007706e0
>>   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>   PKRU: 55555554
>>   Call Trace:
>>    nvme_tcp_queue_rq+0xef/0x330 [nvme_tcp]
>>    blk_mq_dispatch_rq_list+0x11c/0x7c0
>>    ? blk_mq_flush_busy_ctxs+0xf6/0x110
>>    __blk_mq_sched_dispatch_requests+0x12b/0x170
>>    blk_mq_sched_dispatch_requests+0x30/0x60
>>    __blk_mq_run_hw_queue+0x2b/0x60
>>    process_one_work+0x1cb/0x360
>>    ? process_one_work+0x360/0x360
>>    worker_thread+0x30/0x370
>>    ? process_one_work+0x360/0x360
>>    kthread+0x116/0x130
>>    ? kthread_park+0x80/0x80
>>    ret_from_fork+0x1f/0x30
>> --
>>
>> Fixes: cb9b870fba3e ("nvme-tcp: fix wrong setting of request iov_iter")
>> Reported-by: Yi Zhang <yi.zhang@redhat.com>
>> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> Looks good.
>
> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Verified with latest linux-block/for-next.

Tested-by: Yi Zhang <yi.zhang@redhat.com>

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