Re: [PATCH] x86/traps: Mark do_int3() NOKPROBE_SYMBOL

[Li Huafei]

On 2022/3/10 22:04, Masami Hiramatsu wrote:
> On Thu, 10 Mar 2022 20:09:15 +0800
> Li Huafei <lihuafei1@xxxxxxxxxx> wrote:
>
> > Since kprobe_int3_handler() is called in do_int3(), probing do_int3()
> > can cause a breakpoint recursion and crash the kernel. Therefore,
> > do_int3() should be marked as NOKPROBE_SYMBOL.
> >
> > Fixes: 21e28290b317 ("x86/traps: Split int3 handler up")
> > Signed-off-by: Li Huafei <lihuafei1@xxxxxxxxxx>
> Good catch!
> This should be backported to stable kernel.
>
> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Thanks,

Huafei

> Thank you,
>
> > ---
> >   arch/x86/kernel/traps.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> > index c9d566dcf89a..8143693a7ea6 100644
> > --- a/arch/x86/kernel/traps.c
> > +++ b/arch/x86/kernel/traps.c
> > @@ -659,6 +659,7 @@ static bool do_int3(struct pt_regs *regs)
> >   
> >   	return res == NOTIFY_STOP;
> >   }
> > +NOKPROBE_SYMBOL(do_int3);
> >   
> >   static void do_int3_user(struct pt_regs *regs)
> >   {
> > --
> > 2.17.1