Re: Kernel crash in xfs_iflush_cluster (was Somebody take a look please!...)

[Janos Haar]

----- Original Message ----- 
From: "Dave Chinner" <david@xxxxxxxxxxxxx>
To: "Janos Haar" <janos.haar@xxxxxxxxxxxx>
Cc: <xiyou.wangcong@xxxxxxxxx>; <linux-kernel@xxxxxxxxxxxxxxx>; 
<kamezawa.hiroyu@xxxxxxxxxxxxxx>; <linux-mm@xxxxxxxxx>; <xfs@xxxxxxxxxxx>; 
<axboe@xxxxxxxxx>
Sent: Tuesday, April 13, 2010 10:39 AM
Subject: Re: Kernel crash in xfs_iflush_cluster (was Somebody take a look 
please!...)


> On Tue, Apr 13, 2010 at 10:00:17AM +0200, Janos Haar wrote:
> > >On Mon, Apr 12, 2010 at 12:44:37AM +0200, Janos Haar wrote:
> > >>Hi,
> > >>
> > >>Ok, here comes the funny part:
> > >>I have got several messages from the kernel about one of my XFS
> > >>(sdb2) have corrupted inodes, but my xfs_repair (v. 2.8.11) says the
> > >>FS is clean and shine.
> > >>Should i upgrade my xfs_repair, or this is another bug? :-)
> > >
> > >v2.8.11 is positively ancient. :/
> > >
> > >I'd upgrade (current is 3.1.1) and re-run repair again.
> >
> > OK, i will get the new repair today.
> >
> > btw
> > Since i tested the FS with the 2.8.11, today morning i found this in
> > the log:
> >
> > ...
> > Apr 12 00:41:10 alfa kernel: XFS mounting filesystem sdb2   # This
> > was the point of check with xfs_repair v2.8.11
> > Apr 13 03:08:33 alfa kernel: xfs_da_do_buf: bno 32768
> > Apr 13 03:08:33 alfa kernel: dir: inode 474253931
> > Apr 13 03:08:33 alfa kernel: Filesystem "sdb2": XFS internal error
> > xfs_da_do_buf(1) at line 2020 of file fs/xfs/xfs_da_btree.c.  Caller
> > 0xffffffff811c4fa6
>
> A corrupted directory. There have been several different types of
> directory corruption that 2.8.11 didn't detect that 3.1.1 does.
>
> > The entire log is here:
> > http://download.netcenter.hu/bughunt/20100413/messages
>
> So the bad inodes are:
>
> $ awk '/corrupt inode/ { print $10 } /dir: inode/ { print $8 }' messages | 
> sort -n -u
> 474253931
> 474253936
> 474253937
> 474253938
> 474253939
> 474253940
> 474253941
> 474253943
> 474253945
> 474253946
> 474253947
> 474253948
> 474253949
> 474253950
> 474253951
> 673160704
> 673160708
> 673160712
> 673160713
>
> It looks like the bad inodes are confined to two inode clusters. The
> nature of the errors - bad block mappings and bad extent counts -
> makes me think you might have bad memory in the machine:
>
> $ awk '/xfs_da_do_buf: bno/ { printf "%x\n", $8 }' messages | sort -n -u
> 4d8000
> 5e0000
> 7f8001
> 8000
> 8001
> 10000
> 10001
> 20001
> 28001
> 38000
> 270001
> 370001
> 548001
> 568000
> 568001
> 600000
> 600001
> 618000
> 618001
> 628000
> 628001
> 650001
>
> I think they should all be 0 or 1, and:
>
> $ awk '/corrupt inode/ { split($13, a, ")"); printf "%x\n", a[1] }' 
> messages | sort -n -u
> fffffffffd000001
> 6b000001
> 1000001
> 75000001
>
> I think they should all be 1, too.
>
> I've seen this sort of error pattern before on a machine that had a
> bad DIMM.  If the corruption is on disk then the buffers were
> corrupted between the time that the CPU writes to them and being
> written to disk. If there is no corruption on disk, then the CPU is
> reading bad data from memory...
>
> If you run:
>
> $ xfs_db -r -c "inode 474253940" -c p /dev/sdb2
>
> Then I can can confirm whether there is corruption on disk or not.
> Probably best to sample multiple of the inode numbers from the above
> list of bad inodes.

Here is the log:
http://download.netcenter.hu/bughunt/20100413/debug.log

The xfs_db does segmentation fault. :-)

Btw memory corruption:
In the beginnig of march, one of my bets was memory problem too, but the 
server was offline for 7 days, and all the time runs the memtest86 on the 
hw, and passed all the 8GB 74 times without any bit error.
I don't think it is memory problem, additionally the server can create big 
size  .tar.gz files without crc problem.
If i force my mind to think to hw memory problem, i can think only for the 
raid card's cache memory, wich i can't test with memtest86.
Or the cache of the HDD's pcb...

In the other hand, i have seen more people reported memory corruption about 
these kernel versions, can we check this and surely select wich is the 
problem? (hw or sw)?
I mean, if i am right, the hw memory problem makes only 1-2 bit corruption 
seriously, and the sw page handling problem makes bad memory pages, no?

> FWIW, I'd strongly suggest backing up everything you can first
> before running an updated xfs_repair....

Yes, i know that too. :-)

Thanks,
Janos

> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
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