Re: [Xen-devel] [xen-unstable-smoke bisection] complete build-arm64-xsm

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Mar 14, 2018 at 09:01:10AM +0000, Andrew Cooper wrote:
> On 14/03/2018 07:59, Jan Beulich wrote:
> >>>> On 14.03.18 at 03:29, <osstest-admin@xxxxxxxxxxxxxx> wrote:
> >> branch xen-unstable-smoke
> >> xenbranch xen-unstable-smoke
> >> job build-arm64-xsm
> >> testid xen-build
> >>
> >> Tree: qemuu git://xenbits.xen.org/qemu-xen.git
> >> Tree: xen git://xenbits.xen.org/xen.git
> >>
> >> *** Found and reproduced problem changeset ***
> >>
> >>   Bug is in tree:  xen git://xenbits.xen.org/xen.git
> >>   Bug introduced:  b43501451733193b265de30fd79a764363a2a473
> >>   Bug not present: eef83fd2af0d4c78afec34c199c977fc97d8a0b3
> >>   Last fail repro: 
> >> http://logs.test-lab.xenproject.org/osstest/logs/120707/ 
> >>
> >>
> >>   commit b43501451733193b265de30fd79a764363a2a473
> >>   Author: Doug Goldstein <cardoe@xxxxxxxxxx>
> >>   Date:   Mon Mar 12 23:06:51 2018 -0500
> >>   
> >>       tools: detect appropriate debug optimization level
> >>       
> >>       When building debug use -Og as the optimization level if its 
> >> available,
> >>       otherwise retain the use of -O0. -Og has been added by GCC to enable 
> >> all
> >>       optimizations that to not affect debugging while retaining full
> >>       debugability.
> >>       
> >>       Signed-off-by: Doug Goldstein <cardoe@xxxxxxxxxx>
> >>       Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > Sadly altering optimization levels always has the potential of
> > triggering issues like this:
> >
> > xc_dom_arm.c: In function 'meminit':
> > xc_dom_arm.c:446:5: error: 'p2m_size' may be used uninitialized in this 
> > function [-Werror=maybe-uninitialized]
> >      for ( pfn = 0; pfn < p2m_size; pfn++ )
> >      ^
> > cc1: all warnings being treated as errors
> > /home/osstest/build.120709.build-arm64-xsm/xen/tools/libxc/../../tools/Rules.mk:230:
> >  recipe for target 'xc_dom_arm.o' failed
> > make[5]: *** [xc_dom_arm.o] Error 1
> 
> We really should be build testing things at all optimisation levels.  We
> should be ashamed that -O3 gives build failures in most of our major
> components.  (This is yet another item on my TODO list which I've not
> had time to complete.)

I agree with your opinion in general.

In this particular case, I think the compiler is to be blamed. p2m_size
should have been initialised in a previous loop by the time the code
comes to the place gcc complained.

Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel