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From: Hou Pu <houpu.main@gmail.com>
To: amit.engel@dell.com
Cc: linux-nvme@lists.infradead.org, sagi@grimberg.me
Subject: kernel panic due to a missing work initialization in case of zero
Date: Wed, 21 Apr 2021 10:32:05 +0800	[thread overview]
Message-ID: <20210421023205.8743-1-houpu.main@gmail.com> (raw)
In-Reply-To: <BL0PR1901MB2020A15CA929276AB8FC7E52EE489@BL0PR1901MB2020.namprd19.prod.outlook.com>

On 4/20/21 11:46, Engel, Amit wrote:
> Hello,
> 
> We hit a kernel panic as a result of the below sequence:
> In the current nvmet implementation, as part of 'nvmet_start_keep_alive_timer'
> nvmet_keep_alive_timer work will be initialized only if kato != 0
> 
> when nvme connect cmd is being executed with a zero kato value
> 'INIT_DELAYED_WORK(&ctrl->ka_work, nvmet_keep_alive_timer)' will not be called
> 
> once keep alive cmd arrives, we call 'mod_delayed_work' for a work that has not been initialized
> this will lead to kernel WARNING:
> Apr 20 10:32:59 FNM00190700796-A kernel: WARNING: CPU: 11 PID: 75133 at kernel/workqueue.c:1447 __queue_work.cold.55+0xc/0x3c
> And eventually to soft lockup

Hello Engel,

Could you verify this with latest nvme-5.13 branch? I think this
might be the same problem as commit 7b96918a173 (nvmet: avoid
queuing keep-alive timer if it is disabled) fixed.

Thanks,
Hou

> 
> A simple fix for this issue (I will post a patch soon) is to initialize the work (as part of 'nvmet_start_keep_alive_timer') even if kato == 0
> 
> Thanks
> Amit E

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  parent reply	other threads:[~2021-04-21  2:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-20 18:36 kernel panic due to a missing work initialization in case of zero kato value Engel, Amit
2021-04-20 22:24 ` Chaitanya Kulkarni
2021-04-21  2:32 ` Hou Pu [this message]
2021-04-21 13:29   ` kernel panic due to a missing work initialization in case of zero Engel, Amit
2021-04-22 12:16     ` Hou Pu

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