From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754149AbcHAQNf (ORCPT ); Mon, 1 Aug 2016 12:13:35 -0400 Received: from smtprelay0207.hostedemail.com ([216.40.44.207]:42149 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752292AbcHAQN1 (ORCPT ); Mon, 1 Aug 2016 12:13:27 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:3138:3139:3140:3141:3142:3353:3622:3865:3866:3868:3870:3871:3872:3873:3874:5007:6119:6261:6742:7875:7903:10004:10400:10848:10967:11026:11232:11658:11914:12043:12296:12438:12517:12519:12740:13069:13255:13311:13357:13439:14096:14097:14181:14659:14721:21080:21433:30003:30012:30054:30070:30090:30091,0,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,LFtime:2,LUA_SUMMARY:none X-HE-Tag: join58_4ef6134671631 X-Filterd-Recvd-Size: 3010 Date: Mon, 1 Aug 2016 12:05:41 -0400 From: Steven Rostedt To: Josh Poimboeuf Cc: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Linus Torvalds , Brian Gerst , Kees Cook , Peter Zijlstra , Frederic Weisbecker , Byungchul Park Subject: Re: [PATCH 05/19] x86/dumpstack: fix function graph tracing stack dump reliability issues Message-ID: <20160801120541.6bf5c065@gandalf.local.home> In-Reply-To: <20160801155903.wuclx6oys6v4sa66@treble> References: <20160729185521.62a5cd2a@gandalf.local.home> <20160801155903.wuclx6oys6v4sa66@treble> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 1 Aug 2016 10:59:03 -0500 Josh Poimboeuf wrote: > On Fri, Jul 29, 2016 at 06:55:21PM -0400, Steven Rostedt wrote: > > Here's my patch that should be applied on top. > > > > Maybe add a Signed-off-by: Steven Rostedt along > > with your SOB. But you should remain Author. > > [...] > > > @@ -123,13 +124,16 @@ print_context_stack_bp(struct task_struc > > > > while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) { > > unsigned long addr = *ret_addr; > > + unsigned long real_addr; > > > > if (!__kernel_text_address(addr)) > > break; > > > > - addr = ftrace_graph_ret_addr(task, graph, addr); > > - if (ops->address(data, addr, 1)) > > + real_addr = ftrace_graph_ret_addr(task, graph, addr); > > + if (ops->address(data, real_addr, 1)) > > break; > > + if (real_addr != addr) > > + ops->address(data, addr, 0); > > frame = frame->next_frame; > > ret_addr = &frame->return_address; > > } > > Actually this hunk isn't needed because all users of > print_context_stack_bp() only care about "reliable" addresses. With > frame pointers enabled, the only place "unreliable" addresses are used > is in show_trace_log_lvl() -- and it uses the print_context_stack() > callback. > > I rely on that fact in the new frame pointer unwind code: it only > reports reliable addresses. > Can you make this a separate patch then. Before this one, and explain why it isn't needed in the change log. I rather have the current patch not make such a change in logic. -- Steve