From: Mike Snitzer <snitzer@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>,
device-mapper development <dm-devel@redhat.com>
Subject: Re: Kernel v4.1-rc1 + MQ dm-multipath + MQ SRP oops
Date: Wed, 29 Apr 2015 09:43:17 -0400 [thread overview]
Message-ID: <20150429134317.GB23127@redhat.com> (raw)
In-Reply-To: <20150429132403.GB3876@lst.de>
On Wed, Apr 29 2015 at 9:24am -0400,
Christoph Hellwig <hch@lst.de> wrote:
> On Tue, Apr 28, 2015 at 05:54:57PM -0400, Mike Snitzer wrote:
> > Turns out that after running hch's script, with multipathd having setup
> > an mpath device ontop of tcm_loop, if I just do:
> >
> > tcm_loop --unload
> >
> > (tcm_loop appears to allow me to remove the devices out from underneath dm-multipath)
>
> That has nothing to do with tcm_loop. SCSI devices can get unregistered
> any time, and we use refcountin to ensure the structures stay in place
> forever.
>
> See my reply to Bart for what I suspect is the real issue.
Already saw it, see my reply ;)
Your fix only applies to he case where DM_MAPIO_REQUEUE is returned from
map_request() due to .map_rq or .clone_and_map_rq failing. It doesn't
apply to IO completion, example stack here:
https://www.redhat.com/archives/dm-devel/2015-April/msg00157.html
SCSI unregistering shouldn't nuke an in-flight request's queue
(refcounting should work like you say) -- so my crashes are still
unexplained, no?
next prev parent reply other threads:[~2015-04-29 13:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-28 11:52 Kernel v4.1-rc1 + MQ dm-multipath + MQ SRP oops Bart Van Assche
2015-04-28 13:52 ` Mike Snitzer
2015-04-28 21:54 ` Mike Snitzer
2015-04-29 13:24 ` Christoph Hellwig
2015-04-29 13:43 ` Mike Snitzer [this message]
2015-04-29 13:20 ` Christoph Hellwig
2015-04-29 13:34 ` Mike Snitzer
2015-04-29 13:37 ` Christoph Hellwig
2015-04-29 18:53 ` [PATCH] dm: fix free_rq_clone() NULL pointer when requeueing unmapped request Mike Snitzer
2015-04-29 19:11 ` Bart Van Assche
2015-04-29 19:53 ` Mike Snitzer
2015-04-30 9:07 ` Bart Van Assche
2015-04-30 12:57 ` Mike Snitzer
2015-04-30 9:11 ` Aaro Koskinen
2015-04-30 12:56 ` Mike Snitzer
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