Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108

Frederik Deweerdt
2006-09-17T08:15:00Z

On Sat, Sep 16, 2006 at 09:37:45PM +0200, Ingo Molnar wrote:
> --------------->
> Subject: [patch] kprobes: speed INT3 trap handling up on i386
> From: Ingo Molnar <mingo@elte.hu>
>
> speed up kprobes trap handling by special-casing kernel-space
> INT3 traps (which do not occur otherwise) and doing a kprobes
> handler check - instead of redirecting over the i386-die-notifier
> chain.
>
Hi Ingo,

Not that it would make any difference to the actual kprobe performance,
but I think that not using the die-notifier chain makes the DIE_INT3
handling in kprobe_exceptions_notify() useless.

Regards,
Frederik

Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index afe6505..90787ff 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -652,10 +652,6 @@ int __kprobes kprobe_exceptions_notify(s
return ret;

switch (val) {
- case DIE_INT3:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
case DIE_DEBUG:
if (post_kprobe_handler(args->regs))
ret = NOTIFY_STOP;