INFO: task kworker/u4:7:8578 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/u4:7 D24312 8578 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/1:5:16943 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/1:5 D26664 16943 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: 3 locks held by kworker/u4:2/26: #0: ffff8880ae735e18 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x77f/0xe30 kernel/sched/fair.c:10525 #1: ffffc90000e27da8 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff89bc0ec0 (rcu_read_lock){....}-{1:2}, at: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:405 [inline] #2: ffffffff89bc0ec0 (rcu_read_lock){....}-{1:2}, at: batadv_nc_worker+0xf3/0xe50 net/batman-adv/network-coding.c:718 1 lock held by khungtaskd/1149: #0: ffffffff89bc0ec0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6534: #0: ffff8880a6fae430 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 4 locks held by kworker/u4:7/8578: #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: ffffc900019c7da8 (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: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #3: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_exit_net+0x1de/0xba0 net/openvswitch/datapath.c:2491 3 locks held by kworker/1:5/16943: #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: ffffc90001787da8 ((work_completion)(&(&dp->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #2: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x18/0x80 net/openvswitch/datapath.c:2355 2 locks held by syz-executor.3/3926: #0: ffffffff8a817cf0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:741 #1: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #1: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_cmd_new+0x69d/0x1160 net/openvswitch/datapath.c:1690 2 locks held by syz-executor.3/3990: #0: ffffffff8a817cf0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:741 #1: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:105 [inline] #1: ffffffff8aa5dfe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_cmd_new+0x69d/0x1160 net/openvswitch/datapath.c:1690 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1149 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: 3880 Comm: systemd-journal Not tainted 5.8.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:196 Code: 48 89 ef 5d e9 11 4d 3f 00 5d be 03 00 00 00 e9 a6 0a 24 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 48 8b 14 25 00 ff 01 00 65 8b 05 c0 53 8e 7e a9 00 01 ff 00 48 RSP: 0018:ffffc900019a7ad0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff888093328000 RCX: ffff8880937f9f20 RDX: 1ffff92000334f86 RSI: ffffffff815cb5e2 RDI: ffff88809300e4b0 RBP: ffff88809300e300 R08: ffff8880937f9f30 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900019a7c30 R13: 0000000000000000 R14: ffff8880937f9f70 R15: ffffffff815cb590 FS: 00007f26de3168c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f26db1c3008 CR3: 000000009357f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: arch_local_irq_disable arch/x86/include/asm/paravirt.h:770 [inline] devkmsg_poll+0x90/0x210 kernel/printk/printk.c:994 vfs_poll include/linux/poll.h:90 [inline] ep_item_poll+0x14a/0x3e0 fs/eventpoll.c:887 ep_send_events_proc+0x272/0xc50 fs/eventpoll.c:1744 ep_scan_ready_list+0x28f/0x880 fs/eventpoll.c:714 ep_send_events fs/eventpoll.c:1788 [inline] ep_poll fs/eventpoll.c:1944 [inline] do_epoll_wait+0xac4/0x1190 fs/eventpoll.c:2333 __do_sys_epoll_wait fs/eventpoll.c:2343 [inline] __se_sys_epoll_wait fs/eventpoll.c:2340 [inline] __x64_sys_epoll_wait+0x93/0xf0 fs/eventpoll.c:2340 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f26dd5e02e3 Code: Bad RIP value. RSP: 002b:00007ffc25307b78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 000056542024b1e0 RCX: 00007f26dd5e02e3 RDX: 0000000000000013 RSI: 00007ffc25307b80 RDI: 0000000000000008 RBP: 00007ffc25307d70 R08: 000056542024d870 R09: 00007ffc2531a080 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc25307b80 R13: 0000000000000001 R14: 0000000000000000 R15: 0005ab170efdded8