From: Jiri Olsa <jolsa@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Peter Zijlstra <peterz@infradead.org>,
lkml <linux-kernel@vger.kernel.org>,
"bibo,mao" <bibo.mao@intel.com>,
"Ziqian SUN (Zamir)" <zsun@redhat.com>
Subject: Re: [RFC] kretprobe: Prevent triggering kretprobe from within kprobe_flush_task
Date: Tue, 14 Apr 2020 18:03:38 +0200 [thread overview]
Message-ID: <20200414160338.GE208694@krava> (raw)
In-Reply-To: <20200410093159.0d7000a08fd76c2eaf1398f8@kernel.org>
On Fri, Apr 10, 2020 at 09:31:59AM +0900, Masami Hiramatsu wrote:
SNIP
> > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
> > index 4d7022a740ab..081d0f366c99 100644
> > --- a/arch/x86/kernel/kprobes/core.c
> > +++ b/arch/x86/kernel/kprobes/core.c
> > @@ -757,12 +757,33 @@ static struct kprobe kretprobe_kprobe = {
> > .addr = (void *)kretprobe_trampoline,
> > };
> >
> > +void arch_kprobe_reject_section_start(void)
> > +{
> > + struct kprobe_ctlblk *kcb;
> > +
> > + preempt_disable();
> > +
> > + /*
> > + * Set a dummy kprobe for avoiding kretprobe recursion.
> > + * Since kretprobe never run in kprobe handler, kprobe must not
> > + * be running behind this point.
> > + */
> > + __this_cpu_write(current_kprobe, &kretprobe_kprobe);
> > + kcb = get_kprobe_ctlblk();
> > + kcb->kprobe_status = KPROBE_HIT_ACTIVE;
> > +}
>
> Yeah, the code seems good to me.
>
> BTW, I rather like make it arch independent function so that other
> arch can use it. In this case, the dummy kprobe's addr should be
> somewhere obviously blacklisted (but it must be accessible.)
> I think get_kprobe() will be a candidate.
right.. as Ziqian noted we see this on other ppc as well
>
> And (sorry about changing my mind), the naming, I think kprobe_busy_begin()
> and kprobe_busy_end() will be better because it doesn't reject registering
> kprobes, instead, just make it busy :)
ok, will change
thanks,
jirka
next prev parent reply other threads:[~2020-04-14 16:05 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 16:46 [RFC] kretprobe: Prevent triggering kretprobe from within kprobe_flush_task Jiri Olsa
2020-04-09 9:02 ` Naveen N. Rao
2020-04-09 18:43 ` Jiri Olsa
2020-04-09 12:38 ` Masami Hiramatsu
2020-04-09 12:52 ` Jiri Olsa
2020-04-09 14:16 ` Masami Hiramatsu
2020-04-09 13:16 ` Naveen N. Rao
2020-04-09 14:26 ` Masami Hiramatsu
2020-04-09 14:41 ` Masami Hiramatsu
2020-04-09 18:44 ` Jiri Olsa
2020-04-09 20:13 ` Jiri Olsa
2020-04-10 0:31 ` Masami Hiramatsu
2020-04-14 16:03 ` Jiri Olsa [this message]
2020-04-15 9:05 ` [PATCH] " Jiri Olsa
2020-04-16 1:55 ` Masami Hiramatsu
2020-04-16 9:13 ` Jiri Olsa
2020-04-16 13:42 ` Masami Hiramatsu
2020-04-16 14:31 ` [PATCHv2] " Jiri Olsa
2020-04-17 7:38 ` Masami Hiramatsu
2020-04-28 21:36 ` Jiri Olsa
2020-05-01 2:01 ` Masami Hiramatsu
2020-05-07 10:15 ` Jiri Olsa
2020-04-10 1:31 ` [RFC] " Ziqian SUN (Zamir)
2020-04-14 16:03 ` Jiri Olsa
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