From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753622Ab3KZM7G (ORCPT ); Tue, 26 Nov 2013 07:59:06 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:19048 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752889Ab3KZM7B (ORCPT ); Tue, 26 Nov 2013 07:59:01 -0500 Date: Tue, 26 Nov 2013 07:58:59 -0500 From: Steven Rostedt To: Jovi Zhangwei Cc: Masami Hiramatsu , Oleg Nesterov , LKML Subject: Re: [BUG] 3.13-rc1 kernel crash when enable all tracepoints Message-ID: <20131126075859.2060f6fd@gandalf.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.20; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Nov 2013 12:38:53 +0800 Jovi Zhangwei wrote: > Hi, > > I'm not sure this issue already be fixed or not, it can be reproduced > permanently. > > (I didn't use git-bisect yet, you guys might can understand it quickly) > > #echo 1 > /sys/kernel/debug/tracing/events/enable > > [ 160.472176] BUG: unable to handle kernel NULL pointer dereference > at (null) > [ 160.472176] IP: [] strlen+0x0/0x30 I hit this bug last night when testing a fix for another bug. I have a patch for this too, and will send it out after I put it through my tests. You can try it out. -- Steve diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 52594b2..bdac88c 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -372,7 +372,8 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \ __data_size += (len) * sizeof(type); #undef __string -#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1) +#define __string(item, src) __dynamic_array(char, item, \ + strlen((src) ? (src) : "(null)") + 1) #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ @@ -501,7 +502,7 @@ static inline notrace int ftrace_get_offsets_##call( \ #undef __assign_str #define __assign_str(dst, src) \ - strcpy(__get_str(dst), src); + strcpy(__get_str(dst), (src) ? (src) : "(null)"); #undef TP_fast_assign #define TP_fast_assign(args...) args