Re: [PATCH] x86/mm: Disable various instrumentations of mem_encrypt.c

From: Borislav Petkov
Date: Wed Oct 11 2017 - 05:57:42 EST


On Tue, Oct 10, 2017 at 02:45:04PM -0500, Tom Lendacky wrote:
> Some routines in mem_encrypt.c are called very early in the boot process,
> e.g. sme_enable(). When CONFIG_KCOV is defined the resulting code added
> to sme_enable() (and others) for KCOV instrumentation results in a kernel
> crash. Disable the KCOV instrumentation for mem_encrypt.c by adding
> KCOV_INSTRUMENT_mem_encrypt.o := n to arch/x86/mm/Makefile.
>
> In order to avoid other possible early boot issues, model mem_encrypt.c
> after head64.c in regards to tools. In addition to disabling KCOV as
> stated above and a previous patch that disables branch profiling, also
> remove the "-pg" CFLAG if CONFIG_FUNCTION_TRACER is enabled and set
> KASAN_SANITIZE to "n", each of which are done on a file basis.
>
> Reported-by: kernel test robot <lkp@xxxxxx>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> arch/x86/mm/Makefile | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

--
Regards/Gruss,
Boris.

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