From: Chao Leng <lengchao@huawei.com>
To: Sagi Grimberg <sagi@grimberg.me>, <linux-nvme@lists.infradead.org>
Cc: <kbusch@kernel.org>, <axboe@fb.com>, <hch@lst.de>
Subject: Re: [PATCH] nvme-fabrics: fix crash for no IO queues
Date: Tue, 16 Mar 2021 09:23:21 +0800 [thread overview]
Message-ID: <aac125ec-561a-002d-7054-782ee450067e@huawei.com> (raw)
In-Reply-To: <45d16780-79a0-c2e2-8e90-246dae0b3e23@grimberg.me>
On 2021/3/16 1:08, Sagi Grimberg wrote:
>
>>>> A crash happens when set feature(NVME_FEAT_NUM_QUEUES) timeout in nvme
>>>> over rdma(roce) reconnection, the reason is use the queue which is not
>>>> alloced.
>>>>
>>>> If queue is not live, should not allow queue request.
>>>
>>> Can you describe exactly the scenario here? What is the state
>>> here? LIVE? or DELETING?
>> If seting feature(NVME_FEAT_NUM_QUEUES) failed due to time out or
>> the target return 0 io queues, nvme_set_queue_count will return 0,
>> and then reconnection will continue and success. The state of controller
>> is LIVE. The request will continue to deliver by call ->queue_rq(),
>> and then crash happens.
>
> Thinking about this again, we should absolutely fail the reconnection
> when we are unable to set any I/O queues, it is just wrong to
> keep this controller alive...
Keith think keeping the controller alive for diagnose is better.
This is the patch which failed the connection.
https://lore.kernel.org/linux-nvme/20210223072602.3196-1-lengchao@huawei.com/
Now we have 2 choice:
1.failed the connection when unable to set any I/O queues.
2.do not allow queue request when queue is not live.
From a service continuity perspective, I think it is better that failed
the connection when unable to set any I/O queues.
Diagnose is less important, I prefer service continuity, because if failed
the reconnection and then try new reconnection, it is possible to recover.
>
> This should be fixed for both rdma and tcp.
> .
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next prev parent reply other threads:[~2021-03-16 1:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 0:55 [PATCH] nvme-fabrics: fix crash for no IO queues Chao Leng
2021-03-05 20:58 ` Sagi Grimberg
2021-03-08 1:30 ` Chao Leng
2021-03-15 17:08 ` Sagi Grimberg
2021-03-16 1:23 ` Chao Leng [this message]
2021-03-16 2:02 ` Keith Busch
2021-03-16 5:08 ` Sagi Grimberg
2021-03-16 20:57 ` James Smart
2021-03-16 21:25 ` Keith Busch
2021-03-16 23:52 ` Sagi Grimberg
2021-03-17 0:19 ` James Smart
-- strict thread matches above, loose matches on Subject: below --
2021-03-03 2:53 Chao Leng
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