INFO: task kworker/u4:6:12165 blocked for more than 143 seconds. Not tainted 5.9.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:6 state:D stack:24872 pid:12165 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855 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+0x163/0x260 kernel/sched/completion.c:138 __flush_work+0x51f/0xab0 kernel/workqueue.c:3046 flush_all_backlogs net/core/dev.c:5635 [inline] rollback_registered_many+0x552/0x1210 net/core/dev.c:9269 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10429 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10428 ip6gre_exit_batch_net+0x4cf/0x6c0 net/ipv6/ip6_gre.c:1609 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 INFO: task syz-executor.3:26781 blocked for more than 144 seconds. Not tainted 5.9.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:27552 pid:26781 ppid: 7203 flags:0x80004006 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103 tun_detach drivers/net/tun.c:705 [inline] tun_chr_close+0x3a/0x180 drivers/net/tun.c:3408 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:159 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5f9 Code: Bad RIP value. RSP: 002b:00007f2b8598ccf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000118cfe8 RCX: 000000000045d5f9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118cfe8 RBP: 000000000118cfe0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec R13: 000000000169fb6f R14: 00007f2b8598d9c0 R15: 000000000118cfec INFO: task kworker/0:16:2088 blocked for more than 144 seconds. Not tainted 5.9.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:16 state:D stack:24920 pid: 2088 ppid: 2 flags:0x00004000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103 switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 1 lock held by khungtaskd/1169: #0: ffffffff89bd6a40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5829 6 locks held by kworker/1:1H/3868: 1 lock held by in:imklog/6535: #0: ffff8880a1931bb0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 2 locks held by agetty/6765: #0: ffff88809f1f5098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000fa42e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6772: #0: ffff88809707d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000fc02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 5 locks held by kworker/u4:6/12165: #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880a97b5138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900096b7da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7dd6f0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa00 net/core/net_namespace.c:565 #3: ffffffff8a7ea748 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x82/0x6c0 net/ipv6/ip6_gre.c:1606 #4: ffffffff89b91650 (cpu_hotplug_lock){++++}-{0:0}, at: get_online_cpus include/linux/cpu.h:144 [inline] #4: ffffffff89b91650 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:5628 [inline] #4: ffffffff89b91650 (cpu_hotplug_lock){++++}-{0:0}, at: rollback_registered_many+0x45b/0x1210 net/core/dev.c:9269 1 lock held by syz-executor.3/26781: #0: ffffffff8a7ea748 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:705 [inline] #0: ffffffff8a7ea748 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3a/0x180 drivers/net/tun.c:3408 3 locks held by kworker/0:16/2088: #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc9000b357da8 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7ea748 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 2 locks held by kworker/u4:8/17885: 3 locks held by kworker/0:4/21839: #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888214ee5d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc9001886fda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7ea748 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1169 Comm: khungtaskd Not tainted 5.9.0-rc4-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+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3868 Comm: kworker/1:1H Not tainted 5.9.0-rc4-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:4134 [inline] RIP: 0010:__lock_acquire+0x661/0x5570 kernel/locking/lockdep.c:4376 Code: 00 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 74 08 3c 01 0f 8e a4 30 00 00 0f b7 82 b0 00 00 00 66 85 c0 74 06 66 39 c3 <0f> 4f d8 48 8b 04 24 83 c5 01 48 c1 e8 03 42 0f b6 04 28 84 c0 74 RSP: 0018:ffffc900078ef7b0 EFLAGS: 00000002 RAX: 0000000000000003 RBX: 0000000000000004 RCX: ffffffff815a096e RDX: ffffffff8c61e7c0 RSI: 0000000000000008 RDI: ffffffff8c61e870 RBP: 0000000000000002 R08: 0000000000000000 R09: ffffffff8c5f5a57 R10: fffffbfff18beb4a R11: 0000000000000001 R12: 0000000000000388 R13: dffffc0000000000 R14: ffff888098a2a140 R15: ffff888098a2aa28 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020400000 CR3: 000000020ed82000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x94/0xce kernel/locking/spinlock.c:159 snd_seq_client_use_ptr+0x40/0x3e0 sound/core/seq/seq_clientmgr.c:113 get_event_dest_client sound/core/seq/seq_clientmgr.c:504 [inline] snd_seq_deliver_single_event.constprop.0+0xdc/0x820 sound/core/seq/seq_clientmgr.c:612 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:693 [inline] snd_seq_deliver_event+0x2fa/0x850 sound/core/seq/seq_clientmgr.c:828 snd_seq_kernel_client_dispatch+0x145/0x180 sound/core/seq/seq_clientmgr.c:2323 snd_vmidi_output_work+0x1c8/0x380 sound/core/seq/seq_virmidi.c:150 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294