Re: [PATCH 30/32] s390/unwind: Disable KMSAN checks

Alexander Potapenko
2023-11-16T09:05:29Z

On Wed, Nov 15, 2023 at 9:35 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> The unwind code can read uninitialized frames. Furthermore, even in
> the good case, KMSAN does not emit shadow for backchains. Therefore
> disable it for the unwinding functions.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
> arch/s390/kernel/unwind_bc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
> index 0ece156fdd7c..7ecaab24783f 100644
> --- a/arch/s390/kernel/unwind_bc.c
> +++ b/arch/s390/kernel/unwind_bc.c
> @@ -49,6 +49,7 @@ static inline bool is_final_pt_regs(struct unwind_state *state,
> READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE;
> }
>
> +__no_kmsan_checks

Please add some comments to the source file to back this annotation,
so that the intent is not lost in git history.