From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65BDFECDFAA for ; Thu, 12 Jul 2018 21:49:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2283F20883 for ; Thu, 12 Jul 2018 21:49:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2283F20883 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732239AbeGLWBY (ORCPT ); Thu, 12 Jul 2018 18:01:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:45276 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726598AbeGLWBY (ORCPT ); Thu, 12 Jul 2018 18:01:24 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9FC6C2087C; Thu, 12 Jul 2018 21:49:54 +0000 (UTC) Date: Thu, 12 Jul 2018 17:49:52 -0400 From: Steven Rostedt To: Francis Deslauriers Cc: mhiramat@kernel.org, peterz@infradead.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] tracing: kprobes: Prohibit probing on notrace functions Message-ID: <20180712174952.0262b49d@gandalf.local.home> In-Reply-To: <1531418053-21414-2-git-send-email-francis.deslauriers@efficios.com> References: <1500044315-9508-3-git-send-email-francis.deslauriers@efficios.com> <1531418053-21414-1-git-send-email-francis.deslauriers@efficios.com> <1531418053-21414-2-git-send-email-francis.deslauriers@efficios.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 12 Jul 2018 13:54:12 -0400 Francis Deslauriers wrote: > From: Masami Hiramatsu > > Prohibit kprobe-events probing on notrace function. > Since probing on the notrace function can cause recursive > event call. In most case those are just skipped, but > in some case it falls into infinite recursive call. > > Signed-off-by: Masami Hiramatsu > Tested-by: Francis Deslauriers BTW, since you are sending the patch, you must also put in your Signed-off-by too, after Masami's. You can keep the Tested-by. -- Steve > --- > kernel/trace/trace_kprobe.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > index daa8157..952dc2a 100644 > --- a/kernel/trace/trace_kprobe.c > +++ b/kernel/trace/trace_kprobe.c > @@ -487,6 +487,23 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) > return ret; > } > > +#ifdef CONFIG_KPROBES_ON_FTRACE > +static bool within_notrace_func(struct trace_kprobe *tk) > +{ > + unsigned long offset, size, addr; > + > + addr = kallsyms_lookup_name(trace_kprobe_symbol(tk)); > + addr += trace_kprobe_offset(tk); > + > + if (!kallsyms_lookup_size_offset(addr, &size, &offset)) > + return true; /* Out of range. */ > + > + return !ftrace_location_range(addr - offset, addr - offset + size); > +} > +#else > +#define within_notrace_func(tk) (false) > +#endif > + > /* Internal register function - just handle k*probes and flags */ > static int __register_trace_kprobe(struct trace_kprobe *tk) > { > @@ -495,6 +512,12 @@ static int __register_trace_kprobe(struct trace_kprobe *tk) > if (trace_probe_is_registered(&tk->tp)) > return -EINVAL; > > + if (within_notrace_func(tk)) { > + pr_warn("Could not probe notrace function %s\n", > + trace_kprobe_symbol(tk)); > + return -EINVAL; > + } > + > for (i = 0; i < tk->tp.nr_args; i++) > traceprobe_update_arg(&tk->tp.args[i]); >