From: Bart Van Assche <bvanassche@acm.org>
To: Tomas Henzl <thenzl@redhat.com>
Cc: "'linux-scsi@vger.kernel.org'" <linux-scsi@vger.kernel.org>,
Stanislaw Gruszka <sgruszka@redhat.com>,
michaelc@cs.wisc.edu
Subject: Re: [RFC] How to fix an async scan - rmmod race?
Date: Thu, 05 Apr 2012 18:00:44 +0000 [thread overview]
Message-ID: <4F7DDDCC.1070506@acm.org> (raw)
In-Reply-To: <4F7DA4F8.90104@redhat.com>
On 04/05/12 13:58, Tomas Henzl wrote:
> When a rmmod is tried then in some cases the kernel is not able to handle a paging request:
> [ 727.154296] BUG: unable to handle kernel paging request at ffffffffa01874b8
> From what I observerved it happens when when we call the rmmod only a while after a modprobe
> (in this case it is the mpt2sas driver). More accurately said, it happens when rmmod is called
> while scsi async is still at work. The driver is removed but the scsi_host_template is still filled
> with now invalid pointers, in this case it is most likely the hostt->scan_finished which causes the BUG.
Are you sure the above analysis is correct ? I've triggered several
million device removal events with ib_srp but I haven't ever seen the
above crash. Maybe your patch for the SCSI core is hiding a race in the
mpt2sas device removal code.
Bart.
next prev parent reply other threads:[~2012-04-05 18:00 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-05 13:58 [RFC] How to fix an async scan - rmmod race? Tomas Henzl
2012-04-05 15:57 ` Mike Christie
2012-04-05 16:05 ` Mike Christie
2012-04-05 18:00 ` Bart Van Assche [this message]
2012-04-05 21:29 ` Mike Christie
2012-04-06 9:24 ` Bart Van Assche
2012-04-06 17:22 ` Mike Christie
2012-04-06 18:37 ` Bart Van Assche
2012-04-11 21:46 ` Mike Christie
2012-04-06 9:54 ` Tomas Henzl
2012-04-06 15:20 ` James Bottomley
2012-04-06 16:15 ` Bart Van Assche
2012-04-06 16:35 ` James Bottomley
2012-04-06 17:01 ` Bart Van Assche
2012-04-06 17:15 ` James Bottomley
2012-04-06 17:59 ` Bart Van Assche
2012-04-08 17:38 ` Bart Van Assche
2012-04-11 18:17 ` Mike Christie
2012-04-11 18:30 ` Mike Christie
2012-04-11 19:47 ` Bart Van Assche
2012-04-11 22:28 ` Mike Christie
2012-04-12 10:48 ` Bart Van Assche
2012-04-06 9:39 ` Bart Van Assche
2012-04-06 10:14 ` Tomas Henzl
2012-04-06 13:13 ` Tomas Henzl
2012-04-06 14:38 ` Bart Van Assche
2012-04-06 15:32 ` Tomas Henzl
2012-04-12 12:48 ` [RFC] How to fix an async scan - rmmod race? try_module_get Tomas Henzl
2012-04-18 16:48 ` [RFC] How to fix an async scan - 'rmmod --wait' race? Tomas Henzl
2012-04-18 18:18 ` Bart Van Assche
2012-05-17 8:42 ` James Bottomley
2012-05-17 8:55 ` Bart Van Assche
2012-05-17 9:01 ` James Bottomley
2012-05-17 14:51 ` Tomas Henzl
2012-05-22 10:05 ` James Bottomley
2012-05-25 15:13 ` Tomas Henzl
2012-05-25 18:46 ` Dan Williams
2012-05-28 11:58 ` Tomas Henzl
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