Re: [PATCH -tip v3 6/7] kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe

Masami Hiramatsu
2017-09-29T06:48:22Z

On Thu, 28 Sep 2017 09:25:41 +0200
Ingo Molnar <mingo@kernel.org> wrote:

>
> * Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > Actually kprobes doesn't need to disable irq if it is
> > called from ftrace/jump trampoline code because
> > Documentation/kprobes.txt says
> >
> > -----
> > Probe handlers are run with preemption disabled. Depending on the
> > architecture and optimization state, handlers may also run with
> > interrupts disabled (e.g., kretprobe handlers and optimized kprobe
> > handlers run without interrupt disabled on x86/x86-64).
> > -----
> >
> > So let's remove irq disabling from those handlers.
>
> > - local_irq_save(flags);
>
> The title is talking about disable_irq():
>
> kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe
>
> ... but the patch is actually using local_irq_save(), which is an entirely
> different thing! You probably wanted to say:
>
> kprobes/x86: Remove irq disabling from ftrace-based/optimized kprobes

Correct! That's my mistake. thanks!

>
> Also note the plural of 'kprobes' when we refer to them as a generic thing.
>
> I fixed the title, but _please_ read changelogs more carefully before sending
> them.

Thank you again,

>
> Thanks,
>
> Ingo

--
Masami Hiramatsu <mhiramat@kernel.org>