Date: Wed, 10 Jun 2009 23:02:47 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Stefan Bader <stefan.bader@canonical.com>,
       "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: pierre@ossman.eu, linux-kernel@vger.kernel.org,
       Andy Whitcroft <apw@canonical.com>
Subject: Re: [PATCH] mmc: prevent dangling block device from accessing
	stale queues
Message-ID: <20090610210247.GC1381@ucw.cz>
References: <4A280BD4.9080908@canonical.com>
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On Thu 2009-06-04 20:00:52, Stefan Bader wrote:
> Kernel: 2.6.30-rc7 based
> Worked in 2.6.28 (probably only because things went at a different speed)
>
> Testcase: Use ext3/ext4 on a SD card partitioned with one primary DOS 
> partition and leave it mounted while suspend/resume.
>
> Result: After resume the partition table of the SD card has been erased.
>
> The detailed description can be found at:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/383668
>
> In essence the mmc block device frees the generic request queue before 
> the last user of the gendisk has stopped using it leaving an invalid 
> queue pointer which get unfortunately re-used before more requests come 
> in for the old device.
>
> The bugfix will cause more I/O error messages and might not be the 
> ultimate way things should work, but it prevents data from getting lost.

Thanks for finding root cause of this!
								Pavel

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