Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935467AbeAKTAc (ORCPT + 1 other); Thu, 11 Jan 2018 14:00:32 -0500 Received: from mail-it0-f45.google.com ([209.85.214.45]:47020 "EHLO mail-it0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933141AbeAKTAa (ORCPT ); Thu, 11 Jan 2018 14:00:30 -0500 X-Google-Smtp-Source: ACJfBouj1WMEHxUsY3E/eZo/j0bQz+c06Vv7CL3vh9DI+dryMYmu//y4vF7NHPoO7cQl2x5JtEpQXw== From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Thu, 11 Jan 2018 14:00:27 -0500 (EST) X-X-Sender: vince@macbook-air To: Josh Poimboeuf cc: Peter Zijlstra , Vince Weaver , Ingo Molnar , linux-kernel@vger.kernel.org, Ingo Molnar , Arnaldo Carvalho de Melo , Thomas Gleixner , Andy Lutomirski Subject: Re: perf: perf_fuzzer quickly locks up on 4.15-rc7 In-Reply-To: <20180111052538.2qhj6oxnc24xumhk@treble> Message-ID: References: <20180109102507.GG6176@hirez.programming.kicks-ass.net> <20180109132602.GA2369@hirez.programming.kicks-ass.net> <20180109151253.GK6176@hirez.programming.kicks-ass.net> <20180109153341.GL6176@hirez.programming.kicks-ass.net> <20180109160551.GK3040@hirez.programming.kicks-ass.net> <20180109170716.bqmexpmywwr4bwuv@treble> <20180111052538.2qhj6oxnc24xumhk@treble> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, 10 Jan 2018, Josh Poimboeuf wrote: > For the crash, you might try enabling CONFIG_DEBUG_ENTRY and seeing if > that gives you any output. I did enable that, didn't seem to help on the haswell machien at least. > > > > WARNING: can't dereference iret registers at 000000000783fea8 for ip paranoid_entry+0x2e/0x90 > > > > WARNING: can't dereference registers at 00000000f0698d17 for ip paranoid_entry+0x4c/0x90 > > > > WARNING: stack going in the wrong direction? ip=native_sched_clock+0x9/0x90 > > This all looks very weird. The stack pointers -- 000000000783fea8 and > 00000000f0698d17 -- are obviously very wrong. I will try to recreate > locally. On a related note, on a core2 machine with the perf_fuzzer I got this too: Jan 11 13:44:01 core2 kernel: [ 1078.931403] WARNING: stack recursion on stack type 4 Jan 11 13:44:01 core2 kernel: [ 1078.931411] WARNING: can't dereference registers at 000000002c6beb99 for ip swapgs_restore_regs_and_return_to_usermode+0x2b/0x7c Vince