Re: [PATCH v4] riscv: patch: Fixup lockdep warning in stop_machine

From: Changbin Du
Date: Tue Feb 14 2023 - 22:46:02 EST


On Wed, Feb 15, 2023 at 09:24:33AM +0800, Guo Ren wrote:
> On Wed, Feb 15, 2023 at 8:22 AM Conor Dooley <conor@xxxxxxxxxx> wrote:
> >
> > Hey Changbin,
> >
> > On Thu, Feb 02, 2023 at 07:41:16PM +0800, Changbin Du wrote:
> > > The task of ftrace_arch_code_modify(_post)_prepare() caller is
> > > stop_machine, whose caller and work thread are of different tasks. The
> > > lockdep checker needs the same task context, or it's wrong. That means
> > > it's a bug here to use lockdep_assert_held because we don't guarantee
> > > the same task context.
> I'm trying to delete all stop_machine in riscv, from ftrace to kprobe.
> When I have done, we needn't this patch.
>
Which approch would you use? I looked through the riscv-spec, but didn't find any
description abount concurrent modification and execution.

> > >
> > > 2.25.1
> > >
>
>
>
> --
> Best Regards
> Guo Ren

--
Cheers,
Changbin Du