From: sagi@grimberg.me (Sagi Grimberg)
Subject: nvmet: race condition while CQE are getting processed concurrently with the DISCONNECTED event
Date: Wed, 8 Mar 2017 21:34:17 +0200 [thread overview]
Message-ID: <9e9301a7-93a1-20a7-4f4f-d50f26a176e8@grimberg.me> (raw)
In-Reply-To: <20170308154605.GA28937@infradead.org>
>> For that perhaps you can try patch [1].
>
> Yes, I'll think we need that. Did I mention that the percpu
> refounter API is a complete trainwreck a couple times? :)
Heh, You probably did, I wander what is the use-case
for percpu_ref_kill without the guarantee that subsequent
percpu_ref_tryget_live will fail...
>> 2. ib_destroy_cq does not really protect against a case where
>> the work requeue itself because it runs flush_work(). In this
>> case when the work re-executes it polls a cq array that is
>> already freed and sees a bogus successful completion. Perhaps
>> ib_free_cq should run cancel_work_sync() instead? see [2].
>
> Yeah, we'll probably need that as well. Independent of it solves
> the problem reported here.
I'll send proper patches.
Would be nice if Raju or Yi can see if this helps
at all..
next prev parent reply other threads:[~2017-03-08 19:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CY1PR12MB077418C35F6EA2499CBACA45BC2C0@CY1PR12MB0774.namprd12.prod.outlook.com>
2017-03-07 13:33 ` nvmet: race condition while CQE are getting processed concurrently with the DISCONNECTED event Sagi Grimberg
2017-03-08 15:46 ` Christoph Hellwig
2017-03-08 19:34 ` Sagi Grimberg [this message]
[not found] <CY1PR12MB07747089AFFCB6115BBCF5ECBC210@CY1PR12MB0774.namprd12.prod.outlook.com>
2017-03-09 11:45 ` Sagi Grimberg
2017-03-11 8:29 ` Raju Rangoju
2017-03-13 2:22 ` Yi Zhang
2017-03-13 8:05 ` Sagi Grimberg
2017-03-14 13:22 ` Yi Zhang
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