Re: xfstests, bad generic tests 009 and 308

Dave Chinner
2015-09-23T22:12:45Z

On Wed, Sep 23, 2015 at 12:43:21PM +0200, Yann Dupont - Veille Techno wrote:
> Le 22/09/2015 00:52, Dave Chinner a écrit :
> >As it is, I highly recommend that you try a current 4.3 kernel, as
> >there are several code fixes in the XFS kernel code that work
> >around compiler issues we know about. AFAIA, the do_div() asm bug
> >that trips recent gcc optimisations isn't in the upstream kernel
> >yet, but that can be worked around by setting
> >CONFIG_CC_OPTIMIZE_FOR_SIZE=y in your build.
>
> Hi dave,
>
> I can confirm that CONFIG_CC_OPTIMIZE_FOR_SIZE=y is (was ?) the only
> way for me to have reliable XFS kernel code on different arm
> platforms (Marvell kirkwood, Allwinner A20, Amlogic S805), no matter
> what recent gcc version I've been using.
>
> I must admit I was cross-compiling from X86-64 too, but I think (not
> sure) that it was also the case with native gcc.
>
> I must also admit that I didn't tried since some months, because
> CONFIG_CC_OPTIMIZE_FOR_SIZE=y was the silver bullet for arm xfs
> kernel crashes. This crash was difficult to understand because it
> occurs quite randomly (I.e it can take several hours to trigger)
>
> If there's a patch floating around for gcc (or kernel), I'm
> interested to test.

See this subthread from august:

http://oss.sgi.com/archives/xfs/2015-08/msg00234.html

AFAICT, the do_div patch to fix the problem has not yet been picked
up - it's not in the 4.3-rc2 kernel...

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com