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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 E97CAC2D0C0 for ; Mon, 23 Dec 2019 06:05:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B126E20709 for ; Mon, 23 Dec 2019 06:05:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725959AbfLWGFK (ORCPT ); Mon, 23 Dec 2019 01:05:10 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:42544 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id 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X-Received: by 2002:a5d:964e:: with SMTP id d14mr18401819ios.193.1577081108578; Sun, 22 Dec 2019 22:05:08 -0800 (PST) Date: Sun, 22 Dec 2019 22:05:08 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000424dbf059a58cf39@google.com> Subject: INFO: rcu detected stall in bad_area From: syzbot To: christian@brauner.io, ebiederm@xmission.com, linux-kernel@vger.kernel.org, oleg@redhat.com, syzkaller-bugs@googlegroups.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: 2187f215 Merge tag 'for-5.5-rc2-tag' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1207cafee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=ab2ae0615387ef78 dashboard link: https://syzkaller.appspot.com/bug?extid=79fe77a41f0f085ece70 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12cd2951e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144655b6e00000 Bisection is inconclusive: the bug happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16efc199e00000 final crash: https://syzkaller.appspot.com/x/report.txt?x=15efc199e00000 console output: https://syzkaller.appspot.com/x/log.txt?x=11efc199e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+79fe77a41f0f085ece70@syzkaller.appspotmail.com hrtimer: interrupt took 59918 ns rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=9705, q=83) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295004244-4294993742), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor069 R running task 28568 10245 10207 0x80000004 Call Trace: sched_show_task kernel/sched/core.c:5954 [inline] sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5929 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq.cold+0xaf4/0xc02 kernel/rcu/tree.c:2271 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x90/0xe0 kernel/locking/spinlock.c:191 Code: 48 c7 c0 d8 34 93 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 39 48 83 3d 3f f1 ca 01 00 74 24 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 e1 77 88 f9 65 8b 05 d2 da 39 78 RSP: 0000:ffffc90001fe7ca8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff132669b RBX: 0000000000000286 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000006 RDI: 0000000000000286 RBP: ffffc90001fe7cb8 R08: ffff8880914ba100 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888083a2ac00 R13: ffff8880914ba820 R14: 000000000000000a R15: 000000000000000b spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] force_sig_info_to_task+0x2a2/0x340 kernel/signal.c:1329 force_sig_fault_to_task kernel/signal.c:1671 [inline] force_sig_fault+0xbe/0x100 kernel/signal.c:1678 __bad_area_nosemaphore+0x32e/0x420 arch/x86/mm/fault.c:904 __bad_area arch/x86/mm/fault.c:933 [inline] bad_area+0x69/0x80 arch/x86/mm/fault.c:939 do_user_addr_fault arch/x86/mm/fault.c:1404 [inline] __do_page_fault+0x9eb/0xd80 arch/x86/mm/fault.c:1506 do_page_fault+0x38/0x590 arch/x86/mm/fault.c:1530 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1203 RIP: 0033:0x401515 Code: 00 00 00 be b4 fe 4a 00 e8 38 ee ff ff 48 85 c0 0f 85 d2 fe ff ff e9 4a ff ff ff e8 55 d9 04 00 48 6b 44 24 28 18 8b 7c 24 38 <48> 8b 88 50 00 00 20 48 8b 90 48 00 00 20 48 8b b0 40 00 00 20 e8 RSP: 002b:00007f35767f7b20 EFLAGS: 00010206 RAX: 0000000002ed3b50 RBX: 00000000006dcc28 RCX: 0000000000406cd7 RDX: 1482b7b55b3372eb RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00000000006dcc20 R08: 00007f35767f7b20 R09: 00000000006dcc20 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000006dcc2c R13: 00007ffc626d62cf R14: 00007f35767f89c0 R15: 00000000006dcc20 rcu: rcu_preempt kthread starved for 10502 jiffies! g9705 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29272 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1821 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 --- 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#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches