Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755607Ab0FCUHX (ORCPT ); Thu, 3 Jun 2010 16:07:23 -0400 Received: from mga05.intel.com ([192.55.52.89]:46267 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755239Ab0FCUHU (ORCPT ); Thu, 3 Jun 2010 16:07:20 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,356,1272870000"; d="scan'208";a="573104763" Message-ID: <4C080850.1090907@linux.intel.com> Date: Thu, 03 Jun 2010 12:53:52 -0700 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 MIME-Version: 1.0 To: Oleg Nesterov CC: Andrew Morton , Frederic Weisbecker , Ingo Molnar , Roland McGrath , Vegard Nossum , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] x86: make save_stack_address() !CONFIG_FRAME_POINTER friendly References: <20100603193239.GA31530@redhat.com> In-Reply-To: <20100603193239.GA31530@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2131 Lines: 61 On 6/3/2010 12:32 PM, Oleg Nesterov wrote: > If CONFIG_FRAME_POINTER=n, print_context_stack() shouldn't neglect the > non-reliable addresses on stack, this is all we have if dump_trace(bp) > is called with the wrong or zero bp. > > For example, /proc/pid/stack doesn't work if CONFIG_FRAME_POINTER=n. > > This patch obviously has no effect if CONFIG_FRAME_POINTER=y, otherwise > it reverts 1650743c "x86: don't save unreliable stack trace entries". > would be nice if there was a compile time thing to detect if frame pointers are on ratehr than an ifdef. you're now also changing the rules; until now, you would ALWAYS get a backtrace without noise.... now that's changing quite a bit. How are various tools (like perf and sysprof) going to cope with that? > Also, remove the unnecessary type-cast. > > Signed-off-by: Oleg Nesterov > --- > > arch/x86/kernel/stacktrace.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > --- 34-rc1/arch/x86/kernel/stacktrace.c~SAVE_STACK_WO_FP 2010-06-03 18:43:27.000000000 +0200 > +++ 34-rc1/arch/x86/kernel/stacktrace.c 2010-06-03 21:29:52.000000000 +0200 > @@ -26,8 +26,10 @@ static int save_stack_stack(void *data, > static void save_stack_address(void *data, unsigned long addr, int reliable) > { > struct stack_trace *trace = data; > +#ifdef CONFIG_FRAME_POINTER > if (!reliable) > return; > +#endif > if (trace->skip> 0) { > trace->skip--; > return; > @@ -39,9 +41,11 @@ static void save_stack_address(void *dat > static void > save_stack_address_nosched(void *data, unsigned long addr, int reliable) > { > - struct stack_trace *trace = (struct stack_trace *)data; > + struct stack_trace *trace = data; > +#ifdef CONFIG_FRAME_POINTER > if (!reliable) > return; > +#endif > if (in_sched_functions(addr)) > return; > if (trace->skip> 0) { > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/