On 01/05/2011 03:53 PM, Trond Myklebust wrote:

On Wed, 2011-01-05 at 14:40 +0100, Uwe Kleine-K?nig wrote: 

quoted

Hi Russell,

On Wed, Jan 05, 2011 at 11:27:01AM +0000, Russell King - ARM Linux wrote:

quoted

On Wed, Jan 05, 2011 at 12:05:17PM +0100, Uwe Kleine-K?nig wrote:

quoted

Hello Trond,

On Wed, Jan 05, 2011 at 09:40:14AM +0100, Uwe Kleine-K?nig wrote:

quoted

On Mon, Jan 03, 2011 at 07:22:38PM -0500, Trond Myklebust wrote:

quoted

The question is whether this is something happening on the server or the
client. Does an older client kernel boot without any trouble?

I will set up a boot test with 2.6.37 (for statistics) and 2.6.36 to
compare with.  If you don't consider .36 to be old enough let me now.
Once the setup is done it should be easy to test .35 (say), too.

Marc (cc'd) saw similar[1] problems with .37, when using .36.2 the
problems didn't occur.  This was more reliable to trigger and he was so
kind to bisect the problem.

When testing v2.6.36-rc3-51-gafa8ccc init hanged.
(babddc72a9468884ce1a23db3c3d54b0afa299f0 is the first bad commit with
this hang.)  Commit 56e4ebf877b6043c289bda32a5a7385b80c17dee makes the
"init hangs" problem the "fileid changed on tab" problem.

I could only reproduce that on armv5 machines (imx27, imx28 and at91)
but not on armv6 (imx35).

FYI, I've seen the "fileid changed" problem, and it looked like a 32-bit
truncation of the fileid.  It occurred several times on successive
reboots, so I tried to capture a tcpdump trace off the server (Linux
2.6.23-rc8-ga64314e6 - its ancient because I've had issues with buggy
IDE drivers trying to move it forward.)  However, for the last couple
of weeks I've been unable to reproduce it.

The client was based on 2.6.37-rc6.

The "fileid changed" messages popped up after mounting an export with
'nolock,intr,rsize=4096,soft', and then trying to use bash completion
and 'ls' in a few subdirectories - and entries were missing from the
directory lists without 'ls' reporting any errors (which I think is bad
behaviour in itself.)

There was a bug in at least -rc5[1] that was considered already fixed in
-rc4[2]. The later announcements didn't mention it anymore. 

quoted

I don't know why it's stopped producing the errors, although once it
went I never investigated it any further (was far too busy trying to
get AMBA DMA support working.)

It seems it was fixed for most users though. Trond?

As I said, I can't reproduce it.

I'm seeing a lot of mention of ARM above. Is anyone seeing this bug on
x86, or does it appear to be architecture-specific?

It _seems_ to be ARMv5 specific[1]. Uwe did some tests and figured out
that disabling dcache on ARMv5 "fixes" the problem, but
CONFIG_CPU_DCACHE_WRITETHROUGH isn't enough.

[1] Uwe fails to reproduce it on ARMv6. The ARMv6 has a L2 cache and
uses IIRC different instructions to flush the L1 caches. (please correct
me, if I'm wrong, ARM guys :)

cheers, Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

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