From patchwork Wed Jul 15 16:13:37 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 6799391 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id B798D9F3A0 for ; Wed, 15 Jul 2015 16:16:10 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A1DF920654 for ; Wed, 15 Jul 2015 16:16:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 94E582057E for ; Wed, 15 Jul 2015 16:16:08 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZFPJv-0003GS-Kf; Wed, 15 Jul 2015 16:14:07 +0000 Received: from smtprelay0084.hostedemail.com ([216.40.44.84] helo=smtprelay.hostedemail.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZFPJs-0003CU-Hz for linux-arm-kernel@lists.infradead.org; Wed, 15 Jul 2015 16:14:05 +0000 Received: from filter.hostedemail.com (unknown [216.40.38.60]) by smtprelay01.hostedemail.com (Postfix) with ESMTP id 3F20D2341A; Wed, 15 Jul 2015 16:13:40 +0000 (UTC) X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2, 0, 0, , d41d8cd98f00b204, rostedt@goodmis.org, :::::::::::::::::, RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1535:1543:1593:1594:1605:1711:1730:1747:1777:1792:2393:2553:2559:2562:2693:3138:3139:3140:3141:3142:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:4321:5007:6119:6120:6261:7875:7903:7904:8660:9592:10004:10400:10848:10967:11026:11232:11473:11658:11914:12043:12296:12438:12517:12519:12555:12740:13148:13230:14096:14097:21080, 0, RBL:none, CacheIP:none, Bayesian:0.5, 0.5, 0.5, Netcheck:none, DomainCache:0, MSF:not bulk, SPF:fn, MSBL:0, DNSBL:none, Custom_rules:0:0:0 X-HE-Tag: stem24_772779c534663 X-Filterd-Recvd-Size: 5258 Received: from gandalf.local.home (cpe-67-246-153-56.stny.res.rr.com [67.246.153.56]) (Authenticated sender: rostedt@goodmis.org) by omf04.hostedemail.com (Postfix) with ESMTPA; Wed, 15 Jul 2015 16:13:38 +0000 (UTC) Date: Wed, 15 Jul 2015 12:13:37 -0400 From: Steven Rostedt To: AKASHI Takahiro Subject: Re: [RFC 2/3] arm64: refactor save_stack_trace() Message-ID: <20150715121337.3b31aa84@gandalf.local.home> In-Reply-To: <20150715105536.42949ea9@gandalf.local.home> References: <1436765375-7119-1-git-send-email-takahiro.akashi@linaro.org> <1436765375-7119-3-git-send-email-takahiro.akashi@linaro.org> <20150714093154.4d73e551@gandalf.local.home> <55A5A75A.1060401@linaro.org> <20150714225105.6c1e4f15@gandalf.local.home> <55A646EE.6030402@linaro.org> <20150715105536.42949ea9@gandalf.local.home> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.28; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150715_091404_797011_BD8A24B2 X-CRM114-Status: GOOD ( 17.57 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jungseok Lee , catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, broonie@kernel.org, david.griego@linaro.org, olof@lixom.net, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Wed, 15 Jul 2015 10:55:36 -0400 Steven Rostedt wrote: > I'll take a look at it and try to clean up the code. Does the following patch make sense for you? -- Steve diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 3f34496244e9..9384647d07c3 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -18,12 +18,6 @@ #define STACK_TRACE_ENTRIES 500 -#ifdef CC_USING_FENTRY -# define fentry 1 -#else -# define fentry 0 -#endif - static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] = { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX }; static unsigned stack_dump_index[STACK_TRACE_ENTRIES]; @@ -35,7 +29,7 @@ static unsigned stack_dump_index[STACK_TRACE_ENTRIES]; */ static struct stack_trace max_stack_trace = { .max_entries = STACK_TRACE_ENTRIES - 1, - .entries = &stack_dump_trace[1], + .entries = &stack_dump_trace[0], }; static unsigned long max_stack_size; @@ -77,7 +71,7 @@ check_stack(unsigned long ip, unsigned long *stack) unsigned long this_size, flags; unsigned long *p, *top, *start; static int tracer_frame; int frame_size = ACCESS_ONCE(tracer_frame); - int i; + int i, x; this_size = ((unsigned long)stack) & (THREAD_SIZE-1); this_size = THREAD_SIZE - this_size; @@ -105,26 +99,20 @@ check_stack(unsigned long ip, unsigned long *stack) max_stack_size = this_size; max_stack_trace.nr_entries = 0; - - if (using_ftrace_ops_list_func()) - max_stack_trace.skip = 4; - else - max_stack_trace.skip = 3; + max_stack_trace.skip = 0; save_stack_trace(&max_stack_trace); - /* - * Add the passed in ip from the function tracer. - * Searching for this on the stack will skip over - * most of the overhead from the stack tracer itself. - */ - stack_dump_trace[0] = ip; - max_stack_trace.nr_entries++; + /* Skip over the overhead of the stack tracer itself */ + for (i = 0; i < max_stack_trace.nr_entries; i++) { + if (stack_dump_trace[i] == ip) + break; + } /* * Now find where in the stack these are. */ - i = 0; + x = 0; start = stack; top = (unsigned long *) (((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE); @@ -139,12 +127,13 @@ check_stack(unsigned long ip, unsigned long *stack) while (i < max_stack_trace.nr_entries) { int found = 0; - stack_dump_index[i] = this_size; + stack_dump_index[x] = this_size; p = start; for (; p < top && i < max_stack_trace.nr_entries; p++) { if (*p == stack_dump_trace[i]) { - this_size = stack_dump_index[i++] = + stack_dump_trace[x] = stack_dump_trace[i++]; + this_size = stack_dump_index[x++] = (top - p) * sizeof(unsigned long); found = 1; /* Start the search from here */ @@ -168,6 +157,9 @@ check_stack(unsigned long ip, unsigned long *stack) i++; } + for (; x < max_stack_trace.nr_entries; x++) + stack_dump_trace[x] = ULONG_MAX; + if (task_stack_end_corrupted(current)) { print_max_stack(); BUG(); @@ -192,24 +184,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip, if (per_cpu(trace_active, cpu)++ != 0) goto out; - /* - * When fentry is used, the traced function does not get - * its stack frame set up, and we lose the parent. - * The ip is pretty useless because the function tracer - * was called before that function set up its stack frame. - * In this case, we use the parent ip. - * - * By adding the return address of either the parent ip - * or the current ip we can disregard most of the stack usage - * caused by the stack tracer itself. - * - * The function tracer always reports the address of where the - * mcount call was, but the stack will hold the return address. - */ - if (fentry) - ip = parent_ip; - else - ip += MCOUNT_INSN_SIZE; + ip += MCOUNT_INSN_SIZE; check_stack(ip, &stack);