Re: [PATCH V3] riscv: patch_text: Fixup last cpu should be master

[Palmer Dabbelt]

On Wed, 06 Apr 2022 11:13:36 PDT (-0700), Greg KH wrote:
> On Wed, Apr 06, 2022 at 10:16:49PM +0800, guoren@xxxxxxxxxx wrote:
> > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> >
> > These patch_text implementations are using stop_machine_cpuslocked
> > infrastructure with atomic cpu_count. The original idea: When the
> > master CPU patch_text, the others should wait for it. But current
> > implementation is using the first CPU as master, which couldn't
> > guarantee the remaining CPUs are waiting. This patch changes the
> > last CPU as the master to solve the potential risk.
> >
> > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
> > Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
> > Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > ---
> >  arch/riscv/kernel/patch.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> What commit id does this change fix?

I think it's been there since the beginning of our text patching, so

Fixes: 043cb41a85de ("riscv: introduce interfaces to patch kernel code")

seems like the best bet, but I'll go take another look before merging 
it.  That's confusing here, as I acked it, but that was for an earlier 
version that touched more than one arch so it was more ambiguous as to 
which tree it was going through (IIRC I said one of those "LMK if you 
want it through my tree, but here's an Ack in case someone else wants to 
take it" sort of things, as I usually do when it's ambiguous).

Without a changelog, cover letter, or the other patches in the set it's 
kind of hard to tell, though ;)