From: Hannes Reinecke <hare@suse.de>
To: "Ewan D. Milne" <emilne@redhat.com>, linux-scsi@vger.kernel.org
Subject: Re: [PATCH RFC 0/2] avoid crashing when reading /proc/scsi/scsi and simultaneously removing devices
Date: Fri, 18 Dec 2015 10:22:01 +0100 [thread overview]
Message-ID: <5673D039.6060805@suse.de> (raw)
In-Reply-To: <1449583704-32400-1-git-send-email-emilne@redhat.com>
On 12/08/2015 03:08 PM, Ewan D. Milne wrote:
> From: "Ewan D. Milne" <emilne@redhat.com>
>
> The klist traversal used by the reading of /proc/scsi/scsi is not interlocked
> against device removal. It takes a reference on the containing object, but
> this does not prevent the device from being removed from the list. Thus, we
> get errors and eventually panic, as shown in the traces below. Fix this by
> keeping a klist iterator in the seq_file private data.
>
> The problem can be easily reproduced by repeatedly increasing scsi_debug's
> max_luns to 30 and then deleting the devices via sysfs, while simulatenously
> accessing /proc/scsi/scsi.
>
> From a patch originally developed by David Jeffery <djeffery@redhat.com>
>
That's now, what, the third attempt on fixing this?
All previous attempts have been rejected on the grounds that
/proc/scsi/scsi is deprecated and we should allow any updates to it.
Maybe this time we get lucky ...
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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next prev parent reply other threads:[~2015-12-18 9:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-08 14:08 [PATCH RFC 0/2] avoid crashing when reading /proc/scsi/scsi and simultaneously removing devices Ewan D. Milne
2015-12-08 14:08 ` [PATCH RFC 1/2] drivers/base: add bus_device_iter_init, bus_device_iter_next, bus_device_iter_exit Ewan D. Milne
2015-12-18 9:22 ` Hannes Reinecke
2015-12-08 14:08 ` [PATCH RFC 2/2] scsi_proc: Change /proc/scsi/scsi to use bus device iterator Ewan D. Milne
2015-12-18 9:23 ` Hannes Reinecke
2015-12-18 9:22 ` Hannes Reinecke [this message]
2016-01-05 1:58 ` [PATCH RFC 0/2] avoid crashing when reading /proc/scsi/scsi and simultaneously removing devices Martin K. Petersen
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