INFO: task kworker/u4:5:162 blocked for more than 143 seconds. Not tainted 5.7.0-rc7-next-20200529-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D24224 162 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8f3/0x1f80 kernel/sched/core.c:4155 schedule+0xd0/0x2a0 kernel/sched/core.c:4230 schedule_timeout+0x454/0x850 kernel/time/timer.c:1873 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x16a/0x270 kernel/sched/completion.c:138 __flush_work+0x4fd/0xa80 kernel/workqueue.c:3045 flush_all_backlogs net/core/dev.c:5607 [inline] rollback_registered_many+0x562/0xe70 net/core/dev.c:8922 unregister_netdevice_many.part.0+0x16/0x1e0 net/core/dev.c:10088 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10087 ip6gre_exit_batch_net+0x4e8/0x700 net/ipv6/ip6_gre.c:1605 ops_exit_list.isra.0+0x103/0x150 net/core/net_namespace.c:189 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603 process_one_work+0x965/0x1690 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 INFO: task syz-executor.0:11537 can't die for more than 143 seconds. syz-executor.0 D24264 11537 6827 0x00004006 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8f3/0x1f80 kernel/sched/core.c:4155 schedule+0xd0/0x2a0 kernel/sched/core.c:4230 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4289 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7b3/0x13c0 kernel/locking/mutex.c:1103 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1180 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186 setup_net+0x50c/0x860 net/core/net_namespace.c:364 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231 ksys_unshare+0x43d/0x8e0 kernel/fork.c:2989 __do_sys_unshare kernel/fork.c:3057 [inline] __se_sys_unshare kernel/fork.c:3055 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3055 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ca69 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8daa334c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 000000000050aa80 RCX: 000000000045ca69 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040040400 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c66 R14: 00000000004cebf9 R15: 00007f8daa3356d4 Showing all locks held in the system: 5 locks held by kworker/u4:5/162: #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88821b089938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x1690 kernel/workqueue.c:2239 #1: ffffc90001117dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x1690 kernel/workqueue.c:2243 #2: ffffffff8a7a3770 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 net/core/net_namespace.c:565 #3: ffffffff8a7b06e8 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x88/0x700 net/ipv6/ip6_gre.c:1602 #4: ffffffff89b78650 (cpu_hotplug_lock){++++}-{0:0}, at: get_online_cpus include/linux/cpu.h:143 [inline] #4: ffffffff89b78650 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:5600 [inline] #4: ffffffff89b78650 (cpu_hotplug_lock){++++}-{0:0}, at: rollback_registered_many+0x45b/0xe70 net/core/dev.c:8922 1 lock held by khungtaskd/1144: #0: ffffffff89bbde00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 5 locks held by kworker/1:1H/2425: 2 locks held by kworker/1:3/2557: 4 locks held by kworker/1:7/3296: #0: ffff8880ae737e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1261 [inline] #0: ffff8880ae737e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x233/0x1f80 kernel/sched/core.c:4101 #1: ffff8880ae722f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2fb/0x400 kernel/sched/psi.c:817 #2: ffff8880ae7275d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x55/0x190 kernel/time/timer.c:935 #3: ffffffff8cadf058 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x135/0x480 lib/debugobjects.c:636 1 lock held by in:imklog/6505: #0: ffff8880a1df8370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 3 locks held by kworker/0:5/8136: #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a8ea0538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x844/0x1690 kernel/workqueue.c:2239 #1: ffffc90001667dc0 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x878/0x1690 kernel/workqueue.c:2243 #2: ffffffff8a7b06e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4543 2 locks held by syz-executor.0/11537: #0: ffffffff8a7a3770 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x270/0x590 net/core/net_namespace.c:478 #1: ffffffff8a7b06e8 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1180 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1144 Comm: khungtaskd Not tainted 5.7.0-rc7-next-20200529-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e6/0x221 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xf97/0x14e0 kernel/hung_task.c:339 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2425 Comm: kworker/1:1H Not tainted 5.7.0-rc7-next-20200529-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_highpri snd_vmidi_output_work RIP: 0010:check_wait_context kernel/locking/lockdep.c:4068 [inline] RIP: 0010:__lock_acquire+0x5b7/0x48b0 kernel/locking/lockdep.c:4330 Code: 83 ee 01 66 44 89 64 24 50 0f 88 c3 1f 00 00 49 bf 00 00 00 00 00 fc ff df 49 63 c6 48 8d 04 80 4d 8d a4 c5 f9 08 00 00 eb 12 <41> 83 ee 01 49 83 ec 28 41 83 fe ff 0f 84 0e 17 00 00 49 8d 54 24 RSP: 0018:ffffc90007f77768 EFLAGS: 00000046 RAX: 0000000000000009 RBX: 0000000000000001 RCX: 0000000000000001 RDX: ffff8880a0c029d0 RSI: 0000000000000004 RDI: ffffffff8c58f952 RBP: ffff8880a0c029f8 R08: 0000000000000000 R09: fffffbfff18b1147 R10: ffffffff8c588a37 R11: fffffbfff18b1146 R12: ffff8880a0c029f1 R13: ffff8880a0c02080 R14: 0000000000000003 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc074c9ff8 CR3: 000000009f181000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4959 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159 try_to_wake_up+0xa4/0x15a0 kernel/sched/core.c:2544 __wake_up_common+0x147/0x650 kernel/sched/wait.c:93 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123 __snd_rawmidi_transmit_ack+0x25b/0x300 sound/core/rawmidi.c:1259 snd_rawmidi_transmit+0xae/0xf0 sound/core/rawmidi.c:1314 snd_vmidi_output_work+0x109/0x380 sound/core/seq/seq_virmidi.c:144 process_one_work+0x965/0x1690 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293