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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 BAB77C432C0 for ; Tue, 3 Dec 2019 08:27:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CF082053B for ; Tue, 3 Dec 2019 08:27:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726195AbfLCI1J (ORCPT ); Tue, 3 Dec 2019 03:27:09 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:51413 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbfLCI1I (ORCPT ); Tue, 3 Dec 2019 03:27:08 -0500 Received: by mail-io1-f72.google.com with SMTP id t18so1837794iob.18 for ; Tue, 03 Dec 2019 00:27:08 -0800 (PST) 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=3qLCreTXyZIsDgIjHfiKVMA4tqyANILldnEk8jfESE8=; b=S4kBcAA5+4F05RmGBqeUaaQ/qPVNeeQg3UIj0aFxdjnzL6ieUXftpcigiM4Dc2hgLT CjyCygcsom+Pgk0Oaa/8JD6zu3ttoWzZ9ZKhLhET5b5cf0x2mGZ7VNVRMlhcSZF1erUt saO8oMfod4ZGokNXJehc3fBrEVRB6Zh49w95MfJh0gxgFmcRc9MR8kqnqrkxj7UF6GfW U/UM44yLkpfQpeaZfNwSVS4n48KGtNBmXX+saxXPLRrql0rZG230+7lO04Jsv5e2sru2 pcgGXBBpdZwkf+9Il59dEFKiATjPYP+uv44I9gO/T3Tpv78Wkk6zKEpg95iYySoOKWvT osuA== X-Gm-Message-State: APjAAAXk/Zr+Wv2PAElhL+xGFQ3T5dZ5iEtKnvBTnBQYlpXk3zLBpcAR ji/IdXpZ9nCcSzLUamuj8UuPc++LdgFhVuqna5CHx4/bC6A1 X-Google-Smtp-Source: APXvYqwn+P6k3y9w6Cq0pzphn66uiLaaCHB0hMjNGHaoLl0AoPXQJbSORLXS3cfqLLkQishKB4NHhQc2aR6JXBBnz/gIGf2LlD9l MIME-Version: 1.0 X-Received: by 2002:a05:6638:41b:: with SMTP id q27mr4248351jap.135.1575361627739; Tue, 03 Dec 2019 00:27:07 -0800 (PST) Date: Tue, 03 Dec 2019 00:27:07 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000036decf0598c8762e@google.com> Subject: INFO: rcu detected stall in sys_kill From: syzbot To: aarcange@redhat.com, akpm@linux-foundation.org, christian@brauner.io, christian@kellner.me, cyphar@cyphar.com, elena.reshetova@intel.com, jgg@ziepe.ca, keescook@chromium.org, ldv@altlinux.org, linux-kernel@vger.kernel.org, luto@amacapital.net, mingo@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, viro@zeniv.linux.org.uk, wad@chromium.org 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: 596cf45c Merge branch 'akpm' (patches from Andrew) git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15f11c2ae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=9bbcda576154a4b4 dashboard link: https://syzkaller.appspot.com/bug?extid=de8d933e7d153aa0c1bb compiler: clang version 9.0.0 (/home/glider/llvm/clang 80fee25776c2fb61e74c1ecb1a523375c2500b69) 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+de8d933e7d153aa0c1bb@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=6629, q=331) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294953794-4294943291), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.0 R running task 24648 8293 8292 0x0000400a Call Trace: sched_show_task+0x40f/0x560 kernel/sched/core.c:5954 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+0x1861/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:70 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x50 kernel/kcov.c:102 Code: cc 07 48 89 de e8 64 02 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 8b 7e f7 c2 00 01 1f 00 75 2c <8b> 91 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 RSP: 0018:ffffc900021c7c28 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487433 RBX: 0000000000000000 RCX: ffff88809428a100 RDX: 0000000000000001 RSI: 00000000fffffffc RDI: ffffea0002479240 RBP: ffffc900021c7c50 R08: dffffc0000000000 R09: fffffbfff1287025 R10: fffffbfff1287025 R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff888091c57428 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_common kernel/sched/core.c:4236 [inline] preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 __raw_read_unlock include/linux/rwlock_api_smp.h:227 [inline] _raw_read_unlock+0x3a/0x40 kernel/locking/spinlock.c:255 kill_something_info kernel/signal.c:1586 [inline] __do_sys_kill kernel/signal.c:3640 [inline] __se_sys_kill+0x5e9/0x6c0 kernel/signal.c:3634 __x64_sys_kill+0x5b/0x70 kernel/signal.c:3634 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x422a17 Code: 44 00 00 48 c7 c2 d4 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 3e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 dd 32 ff ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff38dca538 EFLAGS: 00000293 ORIG_RAX: 000000000000003e RAX: ffffffffffffffda RBX: 0000000000000064 RCX: 0000000000422a17 RDX: 0000000000000bb8 RSI: 0000000000000009 RDI: 00000000fffffffe RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000001c62940 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000008 R13: 00007fff38dca570 R14: 000000000000f0b6 R15: 00007fff38dca580 rcu: rcu_preempt kthread starved for 10533 jiffies! g6629 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004008 Call Trace: context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 --- This bug is generated by a bot. 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