From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAF16C433DF for ; Thu, 21 May 2020 23:35:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 904BE207D8 for ; Thu, 21 May 2020 23:35:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729771AbgEUXfU (ORCPT ); Thu, 21 May 2020 19:35:20 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:62995 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728706AbgEUXfU (ORCPT ); Thu, 21 May 2020 19:35:20 -0400 Received: from fsav305.sakura.ne.jp (fsav305.sakura.ne.jp [153.120.85.136]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 04LNYvGa068748; Fri, 22 May 2020 08:34:57 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav305.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav305.sakura.ne.jp); Fri, 22 May 2020 08:34:57 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav305.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 04LNYvHw068745 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 22 May 2020 08:34:57 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: [5.7-rc5 x86 regression] ORC unwinder generates unreliable traces To: Thomas Gleixner , x86@kernel.org Cc: Dmitry Vyukov , LKML , Linus Torvalds References: <000000000000c866c705a61a95d4@google.com> <9a337dfa-175f-e13b-1977-0f63d589f37c@I-love.SAKURA.ne.jp> From: Tetsuo Handa Message-ID: <99be7df0-c0af-3985-aa7b-674990e319b2@i-love.sakura.ne.jp> Date: Fri, 22 May 2020 08:34:51 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. syzbot is troubled by CONFIG_UNWINDER_ORC=y . As of commit d2f8825ab78e4c18 ("Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost"), sched_show_task() is defunctional (all threads' traces are marked as 'unreliable'). [ 43.975229] sysrq: Show State [ 43.978609] task PC stack pid father [ 43.981856] systemd S11664 1 0 0x00000000 [ 43.984118] Call Trace: [ 43.985626] ? __schedule+0x27d/0x770 [ 43.987738] ? schedule+0x5a/0xd0 [ 43.989509] ? schedule_hrtimeout_range_clock+0x11c/0x130 [ 43.991702] ? ep_poll+0x461/0x4f0 [ 43.993384] ? _raw_write_unlock_irq+0x1f/0x30 [ 43.995343] ? ep_poll+0x472/0x4f0 [ 43.997053] ? wait_woken+0xa0/0xa0 [ 43.998763] ? do_epoll_wait+0xcd/0xf0 [ 44.000494] ? __x64_sys_epoll_wait+0x15/0x20 [ 44.002385] ? do_syscall_64+0x45/0x1d0 [ 44.004158] ? entry_SYSCALL_64_after_hwframe+0x49/0xb3 Since v5.7-rc5 is bad and v5.7-rc4 is good, the culprit is commit c14cab2688d09b85 ("Merge tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") which contains Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: (...snipped...) - A series of fixes for objtool and the ORC unwinder addressing variety of small issues: in the log. ---------- Kernel 5.7.0-rc6-00069-gd2f8825ab78e on an x86_64 localhost login: [ 43.975229][ C6] sysrq: Show State [ 43.978609][ C6] task PC stack pid father [ 43.981856][ C6] systemd S11664 1 0 0x00000000 [ 43.984118][ C6] Call Trace: [ 43.985626][ C6] ? __schedule+0x27d/0x770 [ 43.987738][ C6] ? schedule+0x5a/0xd0 [ 43.989509][ C6] ? schedule_hrtimeout_range_clock+0x11c/0x130 [ 43.991702][ C6] ? ep_poll+0x461/0x4f0 [ 43.993384][ C6] ? _raw_write_unlock_irq+0x1f/0x30 [ 43.995343][ C6] ? ep_poll+0x472/0x4f0 [ 43.997053][ C6] ? wait_woken+0xa0/0xa0 [ 43.998763][ C6] ? do_epoll_wait+0xcd/0xf0 [ 44.000494][ C6] ? __x64_sys_epoll_wait+0x15/0x20 [ 44.002385][ C6] ? do_syscall_64+0x45/0x1d0 [ 44.004158][ C6] ? entry_SYSCALL_64_after_hwframe+0x49/0xb3 ---------- Kernel 5.7.0-rc5 on an x86_64 localhost login: [ 33.662344][ C6] sysrq: Show State [ 33.663434][ C6] task PC stack pid father [ 33.665144][ C6] systemd S11968 1 0 0x00000000 [ 33.666724][ C6] Call Trace: [ 33.667603][ C6] ? __schedule+0x27d/0x770 [ 33.668692][ C6] ? schedule+0x5a/0xd0 [ 33.669834][ C6] ? schedule_hrtimeout_range_clock+0x11c/0x130 [ 33.671397][ C6] ? ep_poll+0x29e/0x4d0 [ 33.672494][ C6] ? _raw_write_unlock_irq+0x1f/0x30 [ 33.673811][ C6] ? ep_poll+0x45c/0x4d0 [ 33.674839][ C6] ? wait_woken+0xa0/0xa0 [ 33.676000][ C6] ? do_epoll_wait+0xcd/0xf0 [ 33.677184][ C6] ? __x64_sys_epoll_wait+0x15/0x20 [ 33.678433][ C6] ? do_syscall_64+0x45/0x1d0 [ 33.679637][ C6] ? entry_SYSCALL_64_after_hwframe+0x49/0xb3 ---------- Kernel 5.7.0-rc4 on an x86_64 localhost login: [ 35.448925][ C6] sysrq: Show State [ 35.450252][ C6] task PC stack pid father [ 35.452227][ C6] systemd S11944 1 0 0x00000000 [ 35.454001][ C6] Call Trace: [ 35.454983][ C6] ? __schedule+0x27d/0x770 [ 35.456288][ C6] schedule+0x5a/0xd0 [ 35.457393][ C6] schedule_hrtimeout_range_clock+0x11c/0x130 [ 35.459106][ C6] ? ep_poll+0x40b/0x4c0 [ 35.460306][ C6] ? _raw_write_unlock_irq+0x1f/0x30 [ 35.461840][ C6] ep_poll+0x38f/0x4c0 [ 35.463017][ C6] ? wake_up_q+0x90/0x90 [ 35.464230][ C6] do_epoll_wait+0xcd/0xf0 [ 35.465464][ C6] __x64_sys_epoll_wait+0x15/0x20 [ 35.466878][ C6] do_syscall_64+0x45/0x1d0 [ 35.468073][ C6] entry_SYSCALL_64_after_hwframe+0x49/0xb3 [ 35.469657][ C6] RIP: 0033:0x7f1f191b0e93 [ 35.470910][ C6] Code: Bad RIP value. [ 35.472046][ C6] RSP: 002b:00007fffc4c25c88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 [ 35.474303][ C6] RAX: ffffffffffffffda RBX: 00007fffc4c25c90 RCX: 00007f1f191b0e93 [ 35.476852][ C6] RDX: 0000000000000035 RSI: 00007fffc4c25c90 RDI: 0000000000000004 [ 35.479254][ C6] RBP: 00007fffc4c26000 R08: 9c23bff2734474f6 R09: 000055ec811556e0 [ 35.481458][ C6] R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001 [ 35.483643][ C6] R13: ffffffffffffffff R14: 0000000000000000 R15: 000055ec81fd23b0 ----------