From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755241AbcHSQiG (ORCPT ); Fri, 19 Aug 2016 12:38:06 -0400 Received: from mail-it0-f47.google.com ([209.85.214.47]:36618 "EHLO mail-it0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754083AbcHSQiE (ORCPT ); Fri, 19 Aug 2016 12:38:04 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 19 Aug 2016 12:38:01 -0400 (EDT) X-X-Sender: vince@macbook-air To: Vince Weaver cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Borislav Petkov , Ingo Molnar , Arnaldo Carvalho de Melo , Huang Rui Subject: Re: perf: fuzzer crashes immediately on AMD system In-Reply-To: Message-ID: References: <20160819100130.GD10121@twins.programming.kicks-ass.net> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) 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 On Fri, 19 Aug 2016, Vince Weaver wrote: > OK, this is weird. I rebooted (didn't patch the kernel, just rebooted) > and I can't reproduce the original problem at all. I rebooted three more times (after perf_fuzzer turned up a more boring probably known dump, shown at end) and now I am hitting the original bug again. Weird. Let me see if I can figure out what is going on. and for the record, the bug the fuzzer kicks out when it doesn't hit the weird one: note this is sprinkled among thousands of [ 3782.364287] BAD LUCK: lost 7650 message(s) from NMI context! [ 3780.821837] NMI watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [perf_fuzzer:12074] [ 3781.493831] CPU: 2 PID: 12074 Comm: perf_fuzzer Tainted: G L 4.8.0-rc2+ #27 [ 3781.508478] Hardware name: Hewlett-Packard HP Compaq Pro 6305 SFF/1850, BIOS K06 v02.57 08/16/2013 [ 3781.524054] task: ffff8802232cf280 task.stack: ffff8802252c0000 [ 3781.542904] RIP: 0010:[] [] smp_call_function_single+0xbb/0xca [ 3781.558618] RSP: 0018:ffff8802252c3d78 EFLAGS: 00000202 [ 3781.570752] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 [ 3781.584757] RDX: 0000000000000001 RSI: 00000000000008fb RDI: 0000000000000300 [ 3781.598819] RBP: 0000000000000001 R08: 0000000000000003 R09: 00007f0c0ea07700 [ 3781.612930] R10: 00007f0c0ea079d0 R11: 0000000000000206 R12: ffffffff810e226b [ 3781.627107] R13: ffff8802252c3dc8 R14: ffff8802252c3d78 R15: 0000000000000000 [ 3781.641335] FS: 00007f0c0ea07700(0000) GS:ffff88022ed00000(0000) knlGS:0000000000000000 [ 3781.656573] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3781.669534] CR2: 00007f0c0e7d72c8 CR3: 00000002251d1000 CR4: 00000000000407e0 [ 3781.683929] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3781.698410] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000010602 [ 3781.712845] Stack: [ 3781.747577] 0000000000000000 ffffffff810e226b ffff8802252c3dc8 0000000000000003 [ 3781.787434] ffffe8ffffc87190 ffff880223fb7800 ffffffff810e5676 0000000000000000 [ 3781.827415] ffffffff810e18df ffffffff810e16cd 0000000000000000 ffffffff810e13d2 [ 3781.841792] Call Trace: [ 3781.851292] [] ? perf_cgroup_attach+0x34/0x34 [ 3781.864355] [] ? group_sched_out+0x70/0x70 [ 3781.877219] [] ? event_function_call+0xa8/0xa8 [ 3781.890345] [] ? cpu_function_call+0x32/0x3b [ 3781.903284] [] ? perf_ctx_lock+0x1e/0x1e [ 3781.915864] [] ? event_function_call+0x49/0xa8 [ 3781.928952] [] ? group_sched_out+0x70/0x70 [ 3781.941675] [] ? event_function_call+0xa8/0xa8 [ 3781.954734] [] ? perf_event_for_each_child+0x53/0x8a [ 3781.968295] [] ? perf_ioctl+0x41d/0x495 [ 3781.980725] [] ? vfs_ioctl+0x16/0x23 [ 3781.992893] [] ? do_vfs_ioctl+0x46e/0x519 [ 3782.005532] [] ? do_sigaltstack+0xe1/0x1b0 [ 3782.018184] [] ? SyS_ioctl+0x4e/0x71 [ 3782.030319] [] ? entry_SYSCALL_64_fastpath+0x17/0x93 [ 3782.433996] Code: e2 01 74 04 f3 90 eb f4 83 48 18 01 4c 89 e9 4c 89 e2 4c 89 f6 89 ef e8 94 fe ff ff 85 db 74 0d 41 8b 56 18 80 e2 01 74 04 f3 90 f3 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e c3 41 56 41 55 41 89