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From: Sagi Grimberg <sagi@grimberg.me>
To: Chao Leng <lengchao@huawei.com>,
	linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
	Keith Busch <kbusch@kernel.org>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [PATCH 0/3 rfc] Fix nvme-tcp and nvme-rdma controller reset hangs
Date: Mon, 15 Mar 2021 23:25:07 -0700	[thread overview]
Message-ID: <b3094a96-85a8-ef92-9fc3-daecdf683c42@grimberg.me> (raw)
In-Reply-To: <c4df11c9-8d93-add1-396d-b8380d050a08@huawei.com>


>>> We also found Similar deadlocks in the older version.
>>> However, with the latest code, it do not block grabbing the nshead srcu
>>> when ctrl is freezed.
>>> related patches:
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/block/blk-core.c?id=fe2008640ae36e3920cf41507a84fb5d3227435a 
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5a6c35f9af416114588298aa7a90b15bbed15a41 
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/block/blk-core.c?id=ed00aabd5eb9fb44d6aff1173234a2e911b9fead 
>>>
>>> I am not sure they are the same problem.
>>
>> Its not the same problem.
>>
>> When we teardown the io queues, we freeze the namespaces request queues.
>> This means that concurrent mpath submit_bio calls can now block with
>> the srcu lock taken.What is the call trace of ->submit_bio()?
> The requeue work or normal submit bio?

Both.

submit_bio_noacct will try to get the queue->g_usage_counter
(blk_queue_enter), will fail because the queue is frozen, and then will
block until the queue unfreeze will wake it up to try again...

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  reply	other threads:[~2021-03-16  6:25 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15 22:27 [PATCH 0/3 rfc] Fix nvme-tcp and nvme-rdma controller reset hangs Sagi Grimberg
2021-03-15 22:27 ` [PATCH 1/3] nvme: introduce nvme_ctrl_is_mpath helper Sagi Grimberg
2021-03-15 22:27 ` [PATCH 2/3] nvme-tcp: fix possible hang when trying to set a live path during I/O Sagi Grimberg
2021-03-15 22:27 ` [PATCH 3/3] nvme-rdma: " Sagi Grimberg
2021-03-16  3:24 ` [PATCH 0/3 rfc] Fix nvme-tcp and nvme-rdma controller reset hangs Chao Leng
2021-03-16  5:04   ` Sagi Grimberg
2021-03-16  6:18     ` Chao Leng
2021-03-16  6:25       ` Sagi Grimberg [this message]
2021-03-16 20:07 ` Sagi Grimberg
2021-03-16 20:42   ` Keith Busch
2021-03-16 23:51     ` Sagi Grimberg
2021-03-17  2:55       ` Chao Leng
2021-03-17  6:59         ` Christoph Hellwig
2021-03-17  7:59           ` Chao Leng
2021-03-17 18:43             ` Sagi Grimberg
2021-03-18  1:51               ` Chao Leng
2021-03-18  4:45                 ` Christoph Hellwig
2021-03-18 18:46                 ` Sagi Grimberg
2021-03-18 19:16                   ` Keith Busch
2021-03-18 19:31                     ` Sagi Grimberg
2021-03-18 21:52                       ` Keith Busch
2021-03-18 22:45                         ` Sagi Grimberg
2021-03-19 14:05                         ` Christoph Hellwig
2021-03-19 17:28                           ` Christoph Hellwig
2021-03-19 19:07                             ` Keith Busch
2021-03-19 19:34                             ` Sagi Grimberg
2021-03-20  6:11                               ` Christoph Hellwig
2021-03-21  6:49                                 ` Sagi Grimberg
2021-03-22  6:34                                   ` Christoph Hellwig
2021-03-17  8:16           ` Sagi Grimberg

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