Re: [kbuild-all] Re: [ammarfaizi2-block:stable/linux-stable-rc/queue/5.15 146/150] kernel/futex.o: warning: objtool: futex_atomic_op_inuser()+0xb8: unreachable instruction

[Chen, Rong A]

On 5/12/2022 4:17 PM, Peter Zijlstra wrote:
> On Thu, May 12, 2022 at 10:00:33AM +0800, kernel test robot wrote:
> > tree:   https://github.com/ammarfaizi2/linux-block stable/linux-stable-rc/queue/5.15
> > head:   305e905f70311e1b49cc730931a19c3e364f4d8c
> > commit: 45dc9d706619a6814e4063d5431483f94badb5a1 [146/150] x86: Add straight-line-speculation mitigation
> > config: x86_64-randconfig-m001-20220509 (https://download.01.org/0day-ci/archive/20220512/202205120956.qLpGQurX-lkp@xxxxxxxxx/config)
> > compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
> > reproduce (this is a W=1 build):
> >          # https://github.com/ammarfaizi2/linux-block/commit/45dc9d706619a6814e4063d5431483f94badb5a1
> >          git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
> >          git fetch --no-tags ammarfaizi2-block stable/linux-stable-rc/queue/5.15
> >          git checkout 45dc9d706619a6814e4063d5431483f94badb5a1
> >          # save the config file
> >          mkdir build_dir && cp config build_dir/.config
> >          make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All warnings (new ones prefixed by >>):
> >
> > > > kernel/futex.o: warning: objtool: futex_atomic_op_inuser()+0xb8: unreachable instruction
> > --
> > > > mm/madvise.o: warning: objtool: madvise_behavior()+0x69: unreachable instruction
> > --
> > > > kernel/bpf/btf.o: warning: objtool: __btf_resolve_size()+0x72: unreachable instruction
>
> Would it be possible for the robot to include the output of this script:

Hi Peter,

Thanks for your advice, we'll support it asap.

Best Regards,
Rong Chen

>    https://lkml.kernel.org/r/3eb3f091fd6bd9caba50392ceab98ce756804f3b.1650578171.git.jpoimboe@xxxxxxxxxx
>
> for each objtool warning it gives (as run on vmlinux.o):
>
>    $ ./scripts/objdump-func build-output/vmlinux.o futex_atomic_op_inuser
>    $ ./scripts/objdump-func build-output/vmlinux.o madvise_behavior
>    $ ./scripts/objdump-func build-output/vmlinux.o __btf_resolve_size
>
> etc.. that would make it easier to see what the problem is without
> having to reproduce the build.
>
> A super wild guess; but try this commit:
>
>    1ffbe4e935f9 ("objtool: Default ignore INT3 for unreachable")
>
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