INFO: task kworker/1:3:6615 blocked for more than 140 seconds. Not tainted 4.19.114-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:3 D25992 6615 2 0x80000000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3559 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072 addrconf_dad_work+0xa9/0x1110 net/ipv6/addrconf.c:3984 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155 worker_thread+0x96/0xe20 kernel/workqueue.c:2298 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 INFO: task kworker/1:0:22861 blocked for more than 140 seconds. Not tainted 4.19.114-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:0 D29512 22861 2 0x80000000 Workqueue: events linkwatch_event Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3559 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072 linkwatch_event+0xb/0x60 net/core/link_watch.c:236 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155 worker_thread+0x96/0xe20 kernel/workqueue.c:2298 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 INFO: task syz-executor.5:25735 blocked for more than 140 seconds. Not tainted 4.19.114-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D26672 25735 6873 0x80000002 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3559 schedule_timeout+0x896/0xf20 kernel/time/timer.c:1782 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+0x26a/0x3c0 kernel/sched/completion.c:136 __flush_work+0x48b/0x870 kernel/workqueue.c:2928 flush_all_backlogs net/core/dev.c:5276 [inline] rollback_registered_many+0x493/0xc40 net/core/dev.c:8165 rollback_registered+0xf2/0x1c0 net/core/dev.c:8222 unregister_netdevice_queue net/core/dev.c:9275 [inline] unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:9268 unregister_netdevice include/linux/netdevice.h:2614 [inline] __tun_detach+0xd86/0x1020 drivers/net/tun.c:737 tun_detach drivers/net/tun.c:754 [inline] tun_chr_close+0xd9/0x180 drivers/net/tun.c:3261 __fput+0x2cd/0x890 fs/file_table.c:278 task_work_run+0x13f/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xbcd/0x2f30 kernel/exit.c:880 do_group_exit+0x125/0x350 kernel/exit.c:983 get_signal+0x3ec/0x1f90 kernel/signal.c:2588 do_signal+0x8f/0x1710 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x22b/0x2b0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd98bfe7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007fd98bfe86d4 RCX: 000000000045c849 RDX: 0000000020000000 RSI: 0000000000008914 RDI: 0000000000000006 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000006c4 R14: 00000000004c9847 R15: 000000000076bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1073: #0: 00000000b6a865bc (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4436 1 lock held by systemd-udevd/3691: 1 lock held by in:imklog/6177: #0: 00000000b127b433 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767 3 locks held by kworker/1:3/6615: #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000017c19cd1 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x81a/0x1640 kernel/workqueue.c:2126 #1: 00000000bcc6198a ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0x84e/0x1640 kernel/workqueue.c:2130 #2: 000000002ae091ec (rtnl_mutex){+.+.}, at: addrconf_dad_work+0xa9/0x1110 net/ipv6/addrconf.c:3984 3 locks held by kworker/u4:5/7687: 1 lock held by syz-executor.0/14557: 1 lock held by syz-executor.5/21101: #0: 000000002ae091ec (rtnl_mutex){+.+.}, at: tun_detach drivers/net/tun.c:751 [inline] #0: 000000002ae091ec (rtnl_mutex){+.+.}, at: tun_chr_close+0x3a/0x180 drivers/net/tun.c:3261 3 locks held by kworker/1:0/22861: #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000001ea25600 ((wq_completion)"events"){+.+.}, at: process_one_work+0x81a/0x1640 kernel/workqueue.c:2126 #1: 00000000428b93d8 ((linkwatch_work).work){+.+.}, at: process_one_work+0x84e/0x1640 kernel/workqueue.c:2130 #2: 000000002ae091ec (rtnl_mutex){+.+.}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:236 1 lock held by syz-executor.3/25540: 2 locks held by syz-executor.5/25735: #0: 000000002ae091ec (rtnl_mutex){+.+.}, at: tun_detach drivers/net/tun.c:751 [inline] #0: 000000002ae091ec (rtnl_mutex){+.+.}, at: tun_chr_close+0x3a/0x180 drivers/net/tun.c:3261 #1: 000000008682b783 (cpu_hotplug_lock.rw_sem){++++}, at: get_online_cpus include/linux/cpu.h:137 [inline] #1: 000000008682b783 (cpu_hotplug_lock.rw_sem){++++}, at: flush_all_backlogs net/core/dev.c:5269 [inline] #1: 000000008682b783 (cpu_hotplug_lock.rw_sem){++++}, at: rollback_registered_many+0x387/0xc40 net/core/dev.c:8165 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1073 Comm: khungtaskd Not tainted 4.19.114-syzkaller #0 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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x962/0xe40 kernel/hung_task.c:287 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 25540 Comm: syz-executor.3 Not tainted 4.19.114-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:101 Code: 00 00 e9 24 ec ff ff 90 48 8b 34 24 65 48 8b 04 25 40 ee 01 00 65 8b 15 4c 49 9a 7e 81 e2 00 01 1f 00 75 2b 8b 90 d0 12 00 00 <83> fa 02 75 20 48 8b 88 d8 12 00 00 8b 80 d4 12 00 00 48 8b 11 48 RSP: 0000:ffff8881fd6d7c78 EFLAGS: 00000246 RAX: ffff8880a8e9a340 RBX: 0000000000000004 RCX: ffffffff83564e63 RDX: 0000000000000000 RSI: ffffffff83564e6c RDI: 0000000000000005 RBP: ffffffff87aafcc0 R08: ffff8880a8e9a340 R09: ffffed1015cc4733 R10: ffffed1015cc4732 R11: ffff8880ae623993 R12: 0000000000000000 R13: ffffffff87aafc80 R14: ffff8881fd6d7f58 R15: 0000000000000000 FS: 00007f42a97e8700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002a087df8 CR3: 00000002003fa000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: check_preemption_disabled+0x3c/0x280 lib/smp_processor_id.c:15 rcu_dynticks_curr_cpu_in_eqs+0x12/0xa0 kernel/rcu/tree.c:348 rcu_is_watching+0xc/0x20 kernel/rcu/tree.c:1025 rcu_read_lock_sched_held+0x89/0x130 kernel/rcu/update.c:113 trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:57 [inline] fpregs_activate arch/x86/include/asm/fpu/internal.h:517 [inline] user_fpu_begin arch/x86/include/asm/fpu/internal.h:579 [inline] fpu__clear+0x38d/0x410 arch/x86/kernel/fpu/core.c:395 handle_signal arch/x86/kernel/signal.c:772 [inline] do_signal+0xa24/0x1710 arch/x86/kernel/signal.c:823 exit_to_usermode_loop+0x22b/0x2b0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x27b/0x2e0 arch/x86/entry/common.c:198 retint_user+0x8/0x18 RIP: 0033:0x402410 Code: 01 49 83 c5 09 45 39 67 1c 7f ce 48 69 db e8 04 00 00 44 89 b3 04 05 c8 00 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 90 <53> 48 8b 76 10 89 fb 64 8b 04 25 d0 ff ff ff 85 c0 74 3d 48 8d 86 RSP: 002b:00007f42a97e74b8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: 00007f42a97e86d4 RCX: 0000000000416647 RDX: 00007f42a97e74c0 RSI: 00007f42a97e75f0 RDI: 000000000000000b RBP: 000000000076c0e0 R08: 00007f42a97e7a70 R09: 000000000076c0e0 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000beb R14: 00000000004ce0e8 R15: 000000000076c0ec