Re: [RFC PATCH -tip 8/9] error-injection: Fix to not enabling preemption in pre_handler

From: Ingo Molnar
Date: Sat Mar 10 2018 - 03:23:00 EST



* Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Since kprobes pre_handler doesn't need to recover preemption
> even if it modifies regs->ip anymore, this fixes to remove
> the preempt_enable_no_resched() from pre_handler.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
> kernel/fail_function.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/kernel/fail_function.c b/kernel/fail_function.c
> index 21b0122cb39c..b1713521f096 100644
> --- a/kernel/fail_function.c
> +++ b/kernel/fail_function.c
> @@ -176,7 +176,6 @@ static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
> override_function_with_return(regs);
> /* Kprobe specific fixup */
> reset_current_kprobe();
> - preempt_enable_no_resched();
> return 1;
> }

So where did the matching preempt_disable() get removed? If it's the 6/9 patch,
then this patch (and 8/9) should very much be part of it.

There should be no bisection breakage in the series.

Thanks,

Ingo