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INFO: task hung in _rcu_barrier

Status: auto-closed as invalid on 2019/04/13 07:47
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+75cc60c8e9ef0753b83f@syzkaller.appspotmail.com
First crash: 2065d, last: 2022d
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in _rcu_barrier (2) 2 1773d 1785d 0/1 auto-closed as invalid on 2019/10/25 08:36
android-414 INFO: task hung in _rcu_barrier 13 2043d 2062d 0/1 auto-closed as invalid on 2019/03/23 10:41
android-49 INFO: task hung in _rcu_barrier C 1 2001d 1841d 0/3 public: reported C repro on 2019/04/14 08:51
linux-4.19 INFO: task hung in _rcu_barrier 1 860d 860d 0/1 auto-closed as invalid on 2022/04/19 01:50
linux-4.14 INFO: task hung in _rcu_barrier (2) 1 1138d 1138d 0/1 auto-closed as invalid on 2021/07/15 03:03
linux-4.14 INFO: task hung in _rcu_barrier 3 1448d 1480d 0/1 auto-closed as invalid on 2020/09/08 15:22

Sample crash report:
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
INFO: task syz-executor0:14722 blocked for more than 140 seconds.
      Not tainted 4.19.0-rc8+ #284
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D21560 14722  13124 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2825 [inline]
 __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473
 schedule+0xfe/0x460 kernel/sched/core.c:3517
 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common kernel/sched/completion.c:115 [inline]
 wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
 _rcu_barrier+0x49d/0x790 kernel/rcu/tree.c:3478
 rcu_barrier+0x10/0x20 kernel/rcu/tree_plugin.h:834
 netdev_run_todo+0x24d/0xa60 net/core/dev.c:8731
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:117
 tun_detach drivers/net/tun.c:750 [inline]
 tun_chr_close+0xff/0x180 drivers/net/tun.c:3234
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411021
Code: 4c 89 f6 48 89 c7 48 89 ca 48 89 4c 24 10 4c 89 54 24 08 e8 b1 a3 ff ff 48 8b 4c 24 10 41 c6 04 0f 00 4c 8b 7c 24 28 4c 8b 54 <24> 08 45 0f b6 37 e9 db fc ff ff 0f 1f 40 00 41 80 f8 29 74 7f ba
RSP: 002b:00007fff2b384430 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000411021
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 0000000000000000 R08: ffffffff81382a19 R09: 00000000a46703b7
R10: 00007fff2b384360 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 000000000000001f R15: 0000000000000000

Showing all locks held in the system:
3 locks held by kworker/0:1/14:
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
 #1: 00000000935a5f25 (deferred_process_work){+.+.}, at: process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
 #2: 0000000013315750 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
1 lock held by khungtaskd/984:
 #0: 000000000e53632c (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435
1 lock held by rsyslogd/5208:
 #0: 0000000005f1b5e3 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766
2 locks held by getty/5299:
 #0: 000000000de2f932 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 0000000076a4963d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5300:
 #0: 00000000fdcc8588 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 00000000718b8ecf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5301:
 #0: 0000000054bf102f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 00000000b39594bd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5302:
 #0: 00000000ee890110 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 000000009f481a50 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5303:
 #0: 00000000270c6763 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 00000000a8b92fe8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5304:
 #0: 00000000152b9073 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 00000000e02fc462 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5305:
 #0: 00000000ee2100ad (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 00000000b8ba3f69 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
3 locks held by kworker/1:2/5458:
3 locks held by kworker/0:4/5739:
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000d98df2a8 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1b90 kernel/workqueue.c:2124
 #1: 0000000041db9745 ((linkwatch_work).work){+.+.}, at: process_one_work+0xb9a/0x1b90 kernel/workqueue.c:2128
 #2: 0000000013315750 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
1 lock held by syz-executor1/14719:
1 lock held by syz-executor0/14722:
 #0: 00000000e62031c3 (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x144/0x790 kernel/rcu/tree.c:3413

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 984 Comm: khungtaskd Not tainted 4.19.0-rc8+ #284
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
 watchdog+0xb3e/0x1050 kernel/hung_task.c:265
 kthread+0x35a/0x420 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
Sending NMI from CPU 0 to CPUs 1:
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.336 msecs
NMI backtrace for cpu 1
CPU: 1 PID: 14719 Comm: syz-executor1 Not tainted 4.19.0-rc8+ #284
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:update_curr_rt+0x5bd/0xd10 kernel/sched/rt.c:986
Code: 4d 8d 8c 24 50 09 00 00 48 ba 00 00 00 00 00 fc ff df 48 8b 85 30 ff ff ff 4c 89 c9 48 c1 e9 03 80 3c 11 00 0f 85 c2 06 00 00 <4d> 8b 84 24 50 09 00 00 49 8d 8c 24 4c 09 00 00 48 ba 00 00 00 00
RSP: 0018:ffff88017d6e6ac0 EFLAGS: 00000046
RAX: ffff8801daf2d498 RBX: 1ffff1002fadcd5e RCX: 1ffff1003b5e5a92
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8801daf2d4a0
RBP: ffff88017d6e6bb8 R08: ffffed003b5e5a95 R09: ffff8801daf2d490
R10: ffffed003b5e5a94 R11: ffff8801daf2d4a3 R12: ffff8801daf2cb40
R13: ffff8801daf2cb40 R14: ffff8801daf2d4a0 R15: 00000000000065a3
FS:  0000000000d1e940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000706158 CR3: 00000001be8a5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pick_next_task_rt+0x68c/0x940 kernel/sched/rt.c:1567
 pick_next_task kernel/sched/core.c:3332 [inline]
 __schedule+0x1439/0x1ed0 kernel/sched/core.c:3447
 schedule+0xfe/0x460 kernel/sched/core.c:3517
 do_sched_yield+0x1bf/0x2a0 kernel/sched/core.c:4950
 yield+0xb3/0xe0 kernel/sched/core.c:5025
 dev_deactivate_many+0x5d3/0xdd0 net/sched/sch_generic.c:1187
 __dev_close_many+0x197/0x380 net/core/dev.c:1461
 dev_close_many+0x2df/0x860 net/core/dev.c:1499
 rollback_registered_many+0x543/0x1210 net/core/dev.c:7953
 rollback_registered+0x1e9/0x420 net/core/dev.c:8018
 unregister_netdevice_queue+0x321/0x5e0 net/core/dev.c:9062
 unregister_netdevice include/linux/netdevice.h:2599 [inline]
 __tun_detach+0x11b8/0x15c0 drivers/net/tun.c:730
 tun_detach drivers/net/tun.c:747 [inline]
 tun_chr_close+0xe3/0x180 drivers/net/tun.c:3234
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411021
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fffc5950800 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000411021
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 0000000000000000 R08: ffffffff81382a9b R09: 00000000d4cd0b86
R10: 00007fffc5950730 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000025 R15: 0000000000000001

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/10/15 07:46 upstream 35a7f35ad1b1 caf12900 .config console log report ci-upstream-kasan-gce-root
2018/09/02 16:17 upstream 360bd62dc494 a4718693 .config console log report ci-upstream-kasan-gce-root
2018/09/11 04:27 linux-next f2b6e66e9885 8c88323f .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.