Re: [RFC PATCH] arch: patch_text: Fixup last cpu should be master

[Max Filippov]

Hi Guo Ren,

On Sat, Mar 12, 2022 at 7:56 AM <guoren@xxxxxxxxxx> wrote:
>
> From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
>
> These patch_text implementations are using stop_machine_cpuslocked
> infrastructure with atomic cpu_count. The origin idea is that when

The original

> the master CPU patch_text, others should wait for it. But current
> implementation is using the first CPU as master, which couldn't
> guarantee continue CPUs are waiting. This patch changes the last

guarantee that remaining CPUs are waiting.

> CPU as the master to solve the potaintial risk.

potential

>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx
> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Chris Zankel <chris@xxxxxxxxxx>
> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>  arch/arm64/kernel/patching.c      | 4 ++--
>  arch/csky/kernel/probes/kprobes.c | 2 +-
>  arch/riscv/kernel/patch.c         | 2 +-
>  arch/xtensa/kernel/jump_label.c   | 2 +-
>  4 files changed, 5 insertions(+), 5 deletions(-)

Reviewed-by: Max Filippov <jcmvbkbc@xxxxxxxxx>

I'm curious, is there a specific issue that prompted this patch?

-- 
Thanks.
-- Max