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From: "Engel, Amit" <Amit.Engel@Dell.com>
To: "sagi@grimberg.me" <sagi@grimberg.me>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Cc: "Engel, Amit" <Amit.Engel@Dell.com>
Subject: kernel panic due to a missing work initialization in case of zero kato value
Date: Tue, 20 Apr 2021 18:36:05 +0000	[thread overview]
Message-ID: <BL0PR1901MB2020A15CA929276AB8FC7E52EE489@BL0PR1901MB2020.namprd19.prod.outlook.com> (raw)

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

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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             reply	other threads:[~2021-04-20 18:36 UTC|newest]

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

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