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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AA4A4C433FF for ; Wed, 31 Jul 2019 13:56:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8983120693 for ; Wed, 31 Jul 2019 13:56:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729754AbfGaN4k (ORCPT ); Wed, 31 Jul 2019 09:56:40 -0400 Received: from foss.arm.com ([217.140.110.172]:47626 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726693AbfGaN4j (ORCPT ); Wed, 31 Jul 2019 09:56:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EA3BE344; Wed, 31 Jul 2019 06:56:38 -0700 (PDT) Received: from [10.1.196.105] (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 20BCA3F694; Wed, 31 Jul 2019 06:56:38 -0700 (PDT) Subject: Re: [PATCH] Function stack size and its name mismatch in arm64 To: Jiping Ma Cc: Steven Rostedt , mingo@redhat.com, linux-kernel@vger.kernel.org, "linux-arm-kernel@lists.infradead.org" References: <20190731090437.19867-1-jiping.ma2@windriver.com> <20190731065755.5f5bd8a0@gandalf.local.home> From: James Morse Message-ID: <9556feaa-cf38-c101-ed82-2112ea011a88@arm.com> Date: Wed, 31 Jul 2019 14:56:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190731065755.5f5bd8a0@gandalf.local.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jiping, (CC: +linux-arm-kernel) On 31/07/2019 11:57, Steven Rostedt wrote: > On Wed, 31 Jul 2019 17:04:37 +0800 > Jiping Ma wrote: > Note, the subject is not properly written, as it is missing the > subsystem. In this case, it should start with "tracing: " > > >> The PC of one the frame is matched to the next frame function, rather >> than the function of his frame. > > The above change log doesn't make sense. I have no idea what the actual > problem is here. Why is this different for arm64 and no one else? Seems > the bug is with the stack logic code in arm64 not here. Please copy the mailing list for the arm64 arch code too. Is this thing a recent change? arm64's stacktrace code gained some better protection for loops at -rc2. Thanks, James >> diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c >> index 5d16f73898db..ed80b95abf06 100644 >> --- a/kernel/trace/trace_stack.c >> +++ b/kernel/trace/trace_stack.c >> @@ -40,16 +40,28 @@ static void print_max_stack(void) >> >> pr_emerg(" Depth Size Location (%d entries)\n" >> " ----- ---- --------\n", >> +#ifdef CONFIG_ARM64 > > We do not allow arch specific defines in generic code. Otherwise this > would blow up and become unmaintainable. Not to mention it makes the > code ugly and hard to follow. > > Please explain the problem better. I'm sure there's much better ways to > solve this than this patch. > > Thanks, > > -- Steve > > > >> + stack_trace_nr_entries - 1); >> +#else >> stack_trace_nr_entries); >> - >> +#endif >> +#ifdef CONFIG_ARM64 >> + for (i = 1; i < stack_trace_nr_entries; i++) { >> +#else >> for (i = 0; i < stack_trace_nr_entries; i++) { >> +#endif >> if (i + 1 == stack_trace_nr_entries) >> size = stack_trace_index[i]; >> else >> size = stack_trace_index[i] - stack_trace_index[i+1]; >> >> +#ifdef CONFIG_ARM64 >> + pr_emerg("%3ld) %8d %5d %pS\n", i-1, stack_trace_index[i], >> + size, (void *)stack_dump_trace[i-1]); >> +#else >> pr_emerg("%3ld) %8d %5d %pS\n", i, stack_trace_index[i], >> size, (void *)stack_dump_trace[i]); >> +#endif >> } >> } >> >> @@ -324,8 +336,11 @@ static int t_show(struct seq_file *m, void *v) >> seq_printf(m, " Depth Size Location" >> " (%d entries)\n" >> " ----- ---- --------\n", >> +#ifdef CONFIG_ARM64 >> + stack_trace_nr_entries - 1); >> +#else >> stack_trace_nr_entries); >> - >> +#endif >> if (!stack_tracer_enabled && !stack_trace_max_size) >> print_disabled(m); >> >> @@ -334,6 +349,10 @@ static int t_show(struct seq_file *m, void *v) >> >> i = *(long *)v; >> >> +#ifdef CONFIG_ARM64 >> + if (i == 0) >> + return 0; >> +#endif >> if (i >= stack_trace_nr_entries) >> return 0; >> >> @@ -342,9 +361,14 @@ static int t_show(struct seq_file *m, void *v) >> else >> size = stack_trace_index[i] - stack_trace_index[i+1]; >> >> +#ifdef CONFIG_ARM64 >> + seq_printf(m, "%3ld) %8d %5d ", i-1, stack_trace_index[i], size); >> + trace_lookup_stack(m, i-1); >> +#else >> seq_printf(m, "%3ld) %8d %5d ", i, stack_trace_index[i], size); >> >> trace_lookup_stack(m, i); >> +#endif >> >> return 0; >> } >