Re: [LKP] Re: [x86/mm/64] f154f29085: BUG:kernel_reboot-without-warning_in_boot_stage - clang KCOV?

From: Borislav Petkov
Date: Tue Dec 21 2021 - 10:22:16 EST


On Tue, Dec 21, 2021 at 04:10:31PM +0100, Marco Elver wrote:
> Also double-check the Makefile-based solution: the Makefiles in both
> directories already contain various KCOV_INSTRUMENT/K*SAN_SANITIZE :=
> n, so perhaps adding GCOV_PROFILE or GCOV_PROFILE_whicheverfile.o := n
> may be more appropriate should the functions that should not be
> instrumented be a moving target, and prone to breakage again in
> future.

Yeah, I asked whether we should exclude the whole ...cpu/common.c from
profiling - it has mostly init code so it probably doesn't matter
for coverage but no one said anything so I left it to the function
annotation.

And also, I'm still waiting on clang folks to chime in on the New Pass
Manager and whether there's a bug in clang there so that we won't need
the __no_profile annotation at all. I mean, gcc is fine with that config
so unless clang is doing more profiling gunk than gcc and requires that
__llvm_gcov_init constructor... see Nathan's mail upthread.

Thx.

--
Regards/Gruss,
Boris.

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