From: Neil Brown <neilb@suse.de>
To: ml-raid@syscall.eu
Cc: linux-raid@vger.kernel.org
Subject: Re: Possible bug
Date: Wed, 9 Dec 2009 12:57:24 +1100 [thread overview]
Message-ID: <20091209125724.2652d413@notabene.brown> (raw)
In-Reply-To: <4B1E5220.8030500@syscall.eu>
On Tue, 08 Dec 2009 14:18:24 +0100
ml-raid@syscall.eu wrote:
> Hello,
> I have a 2.6.27.29-4-grsec (from http://kernelsec.cr0.org) Linux box, on
> x86, running debian lenny. On sunday, during the monthly rebuild of my
> standard RAID1 setup (/proc/mdstat):
>
> Personalities : [raid1]
> md127 : active raid1 sda1[0] sdb1[1]
> 488383936 blocks [2/2] [UU]
>
> unused devices: <none>
>
> The kernel started outputting thousands of backtraces (see attached log)
> The IO throughput was drastically reduced but the resync finally
> completed after about 38 hours.
>
> This is the first time I have been bitten by this bug. The server has
> been running on this kernel for 74 days and the previous resync didn't
> exhibit any problem.
This is not a RAID problem - it was a problem with the grsec patches.
They assume that any atomic variable is used as a counter and should not
overflow. That is not the case with bd_disk->sync_io. It is expected to
overflow. So the "PAX: ..." report is a false positive.
NeilBrown
next prev parent reply other threads:[~2009-12-09 1:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-08 13:18 Possible bug ml-raid
2009-12-09 1:57 ` Neil Brown [this message]
2009-12-09 9:39 ` ml-raid
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