Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758163AbaAJUKb (ORCPT ); Fri, 10 Jan 2014 15:10:31 -0500 Received: from merlin.infradead.org ([205.233.59.134]:40384 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753182AbaAJUK1 (ORCPT ); Fri, 10 Jan 2014 15:10:27 -0500 Date: Fri, 10 Jan 2014 21:10:20 +0100 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Linux Kernel Mailing List , Aswin Chandramouleeswaran , Scott J Norton , Linus Torvalds Subject: Re: SIGSEGV when using "perf record -g" with 3.13-rc* kernel Message-ID: <20140110201020.GK7572@laptop.programming.kicks-ass.net> References: <52D011C9.7000209@hp.com> <20140110165822.GI7572@laptop.programming.kicks-ass.net> <20140110170223.GD8224@laptop.programming.kicks-ass.net> <52D04BE6.9050907@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52D04BE6.9050907@hp.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 10, 2014 at 02:37:10PM -0500, Waiman Long wrote: > >@@ -641,7 +641,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, > > > > /* Are we prepared to handle this kernel fault? */ > > if (fixup_exception(regs)) { > >- if (current_thread_info()->sig_on_uaccess_error&& signal) { > >+ if (!in_nmi()&& current_thread_info()->sig_on_uaccess_error&& signal) { > > tsk->thread.trap_nr = X86_TRAP_PF; > > tsk->thread.error_code = error_code | PF_USER; > > tsk->thread.cr2 = address; > > Yes, this change fixed the error that I got. I no longer see SIGSEGV when I > run the test. Awesome, just send a more elaborate version that should have the same effect. > I did tried to back out your "perf: Fix arch_perf_out_copy_user default" > patch, but it didn't fix the problem. The culprit was: e00b12e64be9 ("perf/x86: Further optimize copy_from_user_nmi()") -- 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/