Bug#536354: linux-2.6: [s390,lenny] kernel panic during boot

[dann frazier <dannf@debian.org>]

On Thu, Jul 16, 2009 at 03:13:56PM +0200, Frans Pop wrote:
> On Thursday 16 July 2009, Frans Pop wrote:
> > On Wednesday 15 July 2009, dann frazier wrote:
> > > On Mon, Jul 13, 2009 at 11:22:12AM +0200, Frans Pop wrote:
> > > > Linus has committed a different solution: replacing -fwrapv by
> > > > -fno-strict-overflow.
> > > > See upstream commit a137802ee839ace40079bebde24cfb416f73208a.
> > >
> > > I tried applying that fix, but it causes a build failure because the
> > > compiler we use for lenny (gcc-4.1) doesn't support it. It seems
> > > strange that upstream would drop '-fwrapv' due to problems w/
> > > gcc-4.1.x, but then require an option that's not supported by gcc-4.1
> > > at all. Maybe that option got added in the 4.1.x stream after Debian
> > > released it? Maybe I'm missing a kernel change that would prevent
> > > this option from being used in 4.1?
> >
> > That's weird. IIUC the 'call cc-option' function is supposed to check
> > whether an option is supported by the gcc version being used and only
> > actually add it if it is.
> >
> > See Documentation/kbuild/makefiles.txt and scripts/Kbuild.include.
> 
> 2.6.24-17 + Linus' patch builds fine here for s390 with gcc-4.1; 
> the -fno-strict-overflow option is not added.

Found the issue.
linux-2.6 passes the CC flag in an included makefile snippet
(.kernelvariables). Just merging the patch from upstream causes this
sequence to happen:

CC = gcc
Does CC support -fno-strict-overflow? If so, add it to CFLAGS
CC = gcc-4.1

Adjusting the order fixes it..

-- 
dann frazier