INFO: task kworker/u4:0:7 blocked for more than 143 seconds. Not tainted 5.8.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:0 D24960 7 2 0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x1d8/0x250 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+0x163/0x260 kernel/sched/completion.c:138 __flush_work+0x51f/0xab0 kernel/workqueue.c:3046 __cancel_work_timer+0x5de/0x700 kernel/workqueue.c:3133 ovs_exit_net+0x25c/0xba0 net/openvswitch/datapath.c:2496 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186 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 kworker/1:25:19885 blocked for more than 143 seconds. Not tainted 5.8.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:25 D27688 19885 2 0x00004000 Workqueue: events ovs_dp_masks_rebalance Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4312 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 ovs_lock net/openvswitch/datapath.c:105 [inline] ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 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 kworker/0:3:14035 blocked for more than 144 seconds. Not tainted 5.8.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:3 D25888 14035 2 0x00004000 Workqueue: events ovs_dp_masks_rebalance Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4312 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 ovs_lock net/openvswitch/datapath.c:105 [inline] ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 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 kworker/0:22:14040 blocked for more than 144 seconds. Not tainted 5.8.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:22 D28144 14040 2 0x00004000 Workqueue: events ovs_dp_masks_rebalance Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4312 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 ovs_lock net/openvswitch/datapath.c:105 [inline] ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 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 Showing all locks held in the system: 4 locks held by kworker/u4:0/7: #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880a97ad138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90000cdfda8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7ad4b0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa00 net/core/net_namespace.c:565 #3: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #3: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_exit_net+0x1de/0xba0 net/openvswitch/datapath.c:2491 1 lock held by khungtaskd/1152: #0: ffffffff89bc0ec0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 2 locks held by in:imklog/6492: #0: ffff88809a30cd70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 #1: ffff8880ae635e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1261 [inline] #1: ffff8880ae635e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x22d/0x1eb0 kernel/sched/core.c:4124 3 locks held by kworker/1:25/19885: #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: ffffc90009297da8 ((work_completion)(&(&dp->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 3 locks held by kworker/0:3/14035: #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: ffffc90017a07da8 ((work_completion)(&(&dp->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 3 locks held by kworker/0:22/14040: #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: ffffc90017a57da8 ((work_completion)(&(&dp->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #2: ffffffff8aa5e028 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 1 lock held by syz-executor.3/29631: #0: ffffffff8a7ad4b0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1815 1 lock held by syz-executor.3/29683: #0: ffffffff8a7ad4b0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1815 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1152 Comm: khungtaskd Not tainted 5.8.0-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+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: 14302 Comm: kworker/1:19 Not tainted 5.8.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_dev_trap_report_work RIP: 0010:arch_local_irq_restore+0x2e/0x50 arch/x86/include/asm/paravirt.h:765 Code: e0 b4 89 53 48 89 fb 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 18 48 83 3d f9 f7 5b 08 00 74 0c 48 89 df 57 9d <0f> 1f 44 00 00 5b c3 0f 0b 48 c7 c7 80 e0 b4 89 e8 dd 5d 5a 00 eb RSP: 0018:ffffc900183a7af0 EFLAGS: 00000282 RAX: 1ffffffff1369c10 RBX: 0000000000000282 RCX: 1ffffffff1304529 RDX: dffffc0000000000 RSI: ffffffff89bc0e00 RDI: 0000000000000282 RBP: ffff8880900b2180 R08: 0000000000000000 R09: ffffffff8aaf230f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880900b2a50 R14: ffff8880900b2ac8 R15: 0000000000000282 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f40f1321008 CR3: 0000000093a4b000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held_type+0xb0/0xe0 kernel/locking/lockdep.c:4998 lock_is_held include/linux/lockdep.h:425 [inline] rcu_read_lock_sched_held+0x3a/0xb0 kernel/rcu/update.c:135 trace_get_random_bytes include/trace/events/random.h:211 [inline] _get_random_bytes+0x606/0x6d0 drivers/char/random.c:1553 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:529 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:558 [inline] nsim_dev_trap_report_work+0x767/0xbe0 drivers/net/netdevsim/dev.c:599 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