INFO: task kworker/u4:11:30473 blocked for more than 143 seconds. Not tainted 5.8.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:11 D25888 30473 2 0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x91f/0x2250 kernel/sched/core.c:4215 schedule+0xd0/0x2a0 kernel/sched/core.c:4290 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1884 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:5632 [inline] rollback_registered_many+0x55b/0xf60 net/core/dev.c:8953 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10113 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10112 ip6gre_exit_batch_net+0x4cf/0x6c0 net/ipv6/ip6_gre.c:1608 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:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 INFO: task syz-executor.2:15167 blocked for more than 144 seconds. Not tainted 5.8.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27872 15167 7033 0x20024006 Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x91f/0x2250 kernel/sched/core.c:4215 schedule+0xd0/0x2a0 kernel/sched/core.c:4290 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4349 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1180 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186 setup_net+0x502/0x850 net/core/net_namespace.c:364 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:482 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231 ksys_unshare+0x36c/0x9a0 kernel/fork.c:2983 __do_sys_unshare kernel/fork.c:3051 [inline] __se_sys_unshare kernel/fork.c:3049 [inline] __ia32_sys_unshare+0x2c/0x40 kernel/fork.c:3049 do_syscall_32_irqs_on+0x3f/0x60 arch/x86/entry/common.c:428 __do_fast_syscall_32 arch/x86/entry/common.c:475 [inline] do_fast_syscall_32+0x7f/0x120 arch/x86/entry/common.c:503 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7ff5569 Code: Bad RIP value. RSP: 002b:00000000f5dcf0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000136 RAX: ffffffffffffffda RBX: 0000000060060280 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1152: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 6 locks held by kworker/1:1H/2431: 1 lock held by in:imklog/6707: #0: ffff88809699db30 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/6709: #0: ffff888097de0098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900010442e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6717: #0: ffff8880a18cb098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900010602e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6718: #0: ffff888095b90098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900010642e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 3 locks held by kworker/1:4/8076: #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880a80a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90016b1fda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4543 5 locks held by kworker/u4:11/30473: #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88821b03c138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90018827da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7abd30 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa00 net/core/net_namespace.c:565 #3: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x82/0x6c0 net/ipv6/ip6_gre.c:1605 #4: ffffffff89b7ba50 (cpu_hotplug_lock){++++}-{0:0}, at: get_online_cpus include/linux/cpu.h:143 [inline] #4: ffffffff89b7ba50 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:5625 [inline] #4: ffffffff89b7ba50 (cpu_hotplug_lock){++++}-{0:0}, at: rollback_registered_many+0x464/0xf60 net/core/dev.c:8953 3 locks held by kworker/0:1/4122: #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90007e0fda8 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 2 locks held by syz-executor.2/15167: #0: ffffffff8a7abd30 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:478 #1: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1180 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1152 Comm: khungtaskd Not tainted 5.8.0-rc6-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+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: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: 2431 Comm: kworker/1:1H Not tainted 5.8.0-rc6-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:strlen+0x1e/0x90 lib/string.c:544 Code: 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 55 48 89 fd 48 c1 ea 03 53 48 83 ec 08 0f b6 04 02 <48> 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 48 80 7d 00 00 74 39 48 bb RSP: 0018:ffffc90007c5f888 EFLAGS: 00000096 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 1ffffffff11eb61c RSI: ffffffff8a7419f8 RDI: ffffffff88f5b0e0 RBP: ffffffff88f5b0e0 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff8158fa80 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff89ba7c40 R14: ffffffff8a7419f8 R15: ffffc90007c5f968 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000009acf1b4 CR3: 000000003bc33000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: strlen include/linux/string.h:328 [inline] trace_event_get_offsets_lock_acquire include/trace/events/lock.h:13 [inline] perf_trace_lock_acquire+0xbe/0x520 include/trace/events/lock.h:13 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x377/0xad0 kernel/locking/lockdep.c:4958 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:159 queueptr+0x31/0xb0 sound/core/seq/seq_queue.c:210 update_timestamp_of_queue.isra.0+0x20/0x210 sound/core/seq/seq_clientmgr.c:577 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:691 [inline] snd_seq_deliver_event+0x4ca/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:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293