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=1.8 required=3.0 tests=FROM_LOCAL_DIGITS, FROM_LOCAL_HEX,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SORTED_RECIPS, SPF_PASS,URIBL_BLOCKED autolearn=no 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 1209CFD21E1 for ; Mon, 30 Jul 2018 14:27:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B564020893 for ; Mon, 30 Jul 2018 14:27:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B564020893 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727159AbeG3QCS (ORCPT ); Mon, 30 Jul 2018 12:02:18 -0400 Received: from mail-io0-f199.google.com ([209.85.223.199]:38294 "EHLO mail-io0-f199.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726632AbeG3QCS (ORCPT ); Mon, 30 Jul 2018 12:02:18 -0400 Received: by mail-io0-f199.google.com with SMTP id g12-v6so9038047ioh.5 for ; Mon, 30 Jul 2018 07:27:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=q7DS6cdCx8D69vSb5HKNYcsWZOGY1ueAw/ZWiUC8UGw=; b=IwOVtt8G5fDAxuHnwHCzmGuMbms0qHRNgrRtREQIQuQ4kRbHcoyRhnz2Il4KsMlxjZ 12LBfgRE5DVQ3Owm8f3+z93FVGBPR3LgDBKQUcyHiUghUym2ehn5r7njuya2Bh98zIaZ mBhvaRUYCjaB/7cbX2mHflnMq8dlu2XlRV+y2y6rOOcsSC71sYG/CtiaTpjRWN5k2eAv NQCSbfktEfd6MCLTh4q2N8Op1ygN8gOUvuMXN35AHe7BHbwvPSA8zPu47eUrE1w9MiZv pOdLVrxf8ZXhycFC1t0Kf0DrWZzN0LuHAg17uVATONR2WLIwRCQWDBSsa3GciyvUsgYj 3Z0g== X-Gm-Message-State: AOUpUlFqpKz1LGDGWyiFB9OxNThJMb+CJ5N+i3EkQMFnSteJIBjr9wtj b+ayHiTJnECqErslxhtJvmQN/aaDT2YIsma6XzkeDmdeLuPX X-Google-Smtp-Source: AAOMgpdUW3vdZC0/iHQvipHTuB2RRw3p/3g3ggaw0Qx56dJWkdFkayYMJdWYoIhVfaR0hKzzq7ZU78sQvVaOtF0OdYhyW+LFnb8y MIME-Version: 1.0 X-Received: by 2002:a6b:7407:: with SMTP id s7-v6mr6513957iog.78.1532960822856; Mon, 30 Jul 2018 07:27:02 -0700 (PDT) Date: Mon, 30 Jul 2018 07:27:02 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000004d12070572384150@google.com> Subject: INFO: rcu detected stall in snd_seq_oss_write From: syzbot To: akpm@linux-foundation.org, dan.j.williams@intel.com, jglisse@redhat.com, kirill.shutemov@linux.intel.com, ldufour@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, minchan@kernel.org, ross.zwisler@linux.intel.com, syzkaller-bugs@googlegroups.com, willy@infradead.org, ying.huang@intel.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: a26fb01c2879 Merge tag 'random_for_linus_stable' of git://.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=171a2f0c400000 kernel config: https://syzkaller.appspot.com/x/.config?x=ffb4428fdc82f93b dashboard link: https://syzkaller.appspot.com/bug?extid=9f421126464547bed3ee compiler: gcc (GCC) 8.0.1 20180413 (experimental) userspace arch: i386 Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+9f421126464547bed3ee@syzkaller.appspotmail.com INFO: rcu_sched detected stalls on CPUs/tasks: (detected by 1, t=105002 jiffies, g=114619, c=114618, q=1460) All QSes seen, last rcu_sched kthread activity 55292 (4295532443-4295477151), jiffies_till_next_fqs=3, root ->qsmask 0x0 syz-executor3 R running task 21928 9814 4421 0x2002000c Call Trace: sched_show_task.cold.84+0x27a/0x301 kernel/sched/core.c:5324 print_other_cpu_stall.cold.77+0x92f/0x9d2 kernel/rcu/tree.c:1441 check_cpu_stall.isra.60+0x721/0xf70 kernel/rcu/tree.c:1559 __rcu_pending kernel/rcu/tree.c:3244 [inline] rcu_pending kernel/rcu/tree.c:3291 [inline] rcu_check_callbacks+0x23f/0xcd0 kernel/rcu/tree.c:2646 update_process_times+0x2d/0x70 kernel/time/timer.c:1636 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274 __run_hrtimer kernel/time/hrtimer.c:1398 [inline] __hrtimer_run_queues+0x3eb/0x10c0 kernel/time/hrtimer.c:1460 hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] smp_apic_timer_interrupt+0x165/0x730 arch/x86/kernel/apic/apic.c:1050 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 RIP: 0010:arch_local_irq_disable arch/x86/include/asm/paravirt.h:788 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:801 [inline] RIP: 0010:lock_release+0x13c/0xa30 kernel/locking/lockdep.c:3939 Code: 48 89 85 e8 fe ff ff 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 40 07 00 00 48 83 3d 44 95 92 06 00 <0f> 84 53 06 00 00 fa 66 0f 1f 44 00 00 65 4c 8b 3c 25 40 ee 01 00 RSP: 0018:ffff88019c8ff7f0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 1ffff1003391ff03 RCX: ffffc90005236000 RDX: 1ffffffff0fe3616 RSI: 0000000000000000 RDI: ffffffff87f1b0b0 RBP: ffff88019c8ff920 R08: 0000000000000000 R09: 0000000000000000 R10: ffff88019907c978 R11: b21129c27367def3 R12: ffff88019c8ff8f8 R13: ffff8801abf50bc8 R14: ffff88019c8ffa20 R15: ffff88019907c140 __might_fault+0x19e/0x1e0 mm/memory.c:4564 _copy_from_user+0x30/0x150 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] snd_seq_oss_write+0x188/0xb70 sound/core/seq/oss/seq_oss_rw.c:106 odev_write+0x59/0x90 sound/core/seq/oss/seq_oss.c:177 __vfs_write+0x117/0x9f0 fs/read_write.c:485 vfs_write+0x1f8/0x560 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __ia32_sys_write+0x71/0xb0 fs/read_write.c:607 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f87cb9 Code: 55 08 8b 88 64 cd ff ff 8b 98 68 cd ff ff 89 c8 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 1c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5f410cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 000000000000001b RCX: 0000000020000240 RDX: 00000000fffffe71 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_sched kthread starved for 55292 jiffies! g114619 c114618 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 RCU grace-period kthread stack dump: rcu_sched R running task 23688 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2853 [inline] __schedule+0x87c/0x1ec0 kernel/sched/core.c:3501 schedule+0xfb/0x450 kernel/sched/core.c:3545 schedule_timeout+0x140/0x260 kernel/time/timer.c:1801 rcu_gp_kthread+0x717/0x1c90 kernel/rcu/tree.c:2179 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.