Re: [tip:locking/kcsan 12/12] /bin/bash: line 1: 61526 Segmentation fault sparse ...

From: Peter Zijlstra
Date: Thu May 28 2020 - 04:00:32 EST


On Thu, May 28, 2020 at 01:54:42AM +0200, Borislav Petkov wrote:
> On Thu, May 28, 2020 at 07:39:31AM +0800, kbuild test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/kcsan
> > head: a5dead405f6be1fb80555bdcb77c406bf133fdc8
> > commit: a5dead405f6be1fb80555bdcb77c406bf133fdc8 [12/12] compiler_types.h: Optimize __unqual_scalar_typeof compilation time
> > config: i386-randconfig-s002-20200527 (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
> > reproduce:
> > # apt-get install sparse
> > # sparse version: v0.6.1-240-gf0fe1cd9-dirty
> > git checkout a5dead405f6be1fb80555bdcb77c406bf133fdc8
> > # save the attached .config to linux build tree
> > make W=1 C=1 ARCH=i386 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> >
> > All errors (new ones prefixed by >>, old ones prefixed by <<):
>
> I'll say.
>
> Looking at the subject, that broke the 0day bot too. :-)
>
> /me trims it.
>
> Looks like we need __CHECKER__ ifdeffery somewhere but it is too late
> for me to think straight so tomorrow...

I think the problem is that sparse can't parse the C11 _Generic thing.
Someone needs to teach it new tricks.