Re: vmlinux.o: warning: objtool: mce_wrmsrl.constprop.0()+0x6b: call to __sanitizer_cov_trace_pc() leaves .noinstr.text section

[Borislav Petkov]

On Sun, Aug 22, 2021 at 01:39:40PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   9ff50bf2f2ff5fab01cac26d8eed21a89308e6ef
> commit: e100777016fdf6ec3a9d7c1773b15a2b5eca6c55 x86/mce: Annotate mce_rd/wrmsrl() with noinstr
> date:   11 months ago
> config: x86_64-buildonly-randconfig-r003-20210822 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e100777016fdf6ec3a9d7c1773b15a2b5eca6c55
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout e100777016fdf6ec3a9d7c1773b15a2b5eca6c55
>         # save the attached .config to linux build tree
>         mkdir build_dir
>         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 >>):
> 
> >> vmlinux.o: warning: objtool: mce_wrmsrl.constprop.0()+0x6b: call to __sanitizer_cov_trace_pc() leaves .noinstr.text section
>    vmlinux.o: warning: objtool: do_machine_check()+0xe1a: call to mce_panic.isra.0() leaves .noinstr.text section
>    vmlinux.o: warning: objtool: exc_machine_check()+0x1af: call to __sanitizer_cov_trace_pc() leaves .noinstr.text section
>    vmlinux.o: warning: objtool: lock_is_held_type()+0x3c: call to check_flags() leaves .noinstr.text section
>    vmlinux.o: warning: objtool: __context_tracking_enter()+0x9d: call to __sanitizer_cov_trace_pc() leaves .noinstr.text section
>    vmlinux.o: warning: objtool: __context_tracking_exit()+0x42: call to __sanitizer_cov_trace_pc() leaves .noinstr.text section

The sanitizer stuff is being NOPed out with newer compilers, says
peterz. And I can confirm after testing with your .config and with
gcc-11.

The mce_panic() thing I'm working on.

-- 
Regards/Gruss,
    Boris.

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