syzbot

IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
INFO: task kworker/u4:3:210 blocked for more than 140 seconds.
      Not tainted 4.19.190-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:3    D25568   210      2 0x80000000
Workqueue: netns cleanup_net
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
IPVS: ftp: loaded support on port[0] = 21
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common+0x29c/0x470 kernel/sched/completion.c:115
 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2712
 flush_scheduled_work include/linux/workqueue.h:599 [inline]
 tipc_exit_net+0x38/0x60 net/tipc/core.c:100
 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153
 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553
 process_one_work+0x864/0x1570 kernel/workqueue.c:2152
IPVS: ftp: loaded support on port[0] = 21
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2295
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Showing all locks held in the system:
3 locks held by kworker/u4:3/210:
 #0: 00000000d8e26b16 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
 #1: 00000000e43a7099 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
 #2: 00000000bf628681 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:520
1 lock held by khungtaskd/1569:
 #0: 0000000093741e38 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7796:
 #0: 00000000106010b4 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
3 locks held by kworker/0:2/8149:
 #0: 00000000b97b17a4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
IPVS: ftp: loaded support on port[0] = 21
 #1: 000000006883d179 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
 #2: 00000000b238114b (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline]
 #2: 00000000b238114b (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314
2 locks held by kworker/1:3/9294:
 #0: 00000000dd554ee4 ((wq_completion)"rcu_gp"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
 #1: 00000000ebae28f4 ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
3 locks held by kworker/1:4/9463:
 #0: 00000000b97b17a4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
 #1: 00000000c23b5234 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
 #2: 00000000a66abe76 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline]
 #2: 00000000a66abe76 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314
3 locks held by kworker/0:5/10464:
 #0: 00000000b97b17a4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
 #1: 00000000f9e9a8f3 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
 #2: 0000000083544ae2 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline]
 #2: 0000000083544ae2 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314
IPVS: ftp: loaded support on port[0] = 21
3 locks held by kworker/0:6/10509:
 #0: 00000000b97b17a4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2123
 #1: 00000000a8320572 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2127
 #2: 00000000244d56a2 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline]
 #2: 00000000244d56a2 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314
1 lock held by syz-executor810/30008:
 #0: 0000000074e0c15e (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
 #0: 0000000074e0c15e (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667
1 lock held by syz-executor810/30031:
 #0: 0000000074e0c15e (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: 0000000074e0c15e (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x256/0x6f0 kernel/rcu/tree_exp.h:667
2 locks held by syz-executor810/30032:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1569 Comm: khungtaskd Not tainted 4.19.190-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+0x1fc/0x2ef lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
IPVS: ftp: loaded support on port[0] = 21
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8101 Comm: syz-executor810 Not tainted 4.19.190-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__lock_acquire+0x1fc/0x3ff0 kernel/locking/lockdep.c:3295
Code: 5c 41 5d 41 5e 41 5f c3 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 80 3c 02 00 0f 85 b3 2a 00 00 49 81 3e 20 d2 66 8c <0f> 84 65 ff ff ff 83 fe 01 0f 87 68 ff ff ff 48 ba 00 00 00 00 00
RSP: 0018:ffff8880ba107a20 EFLAGS: 00000006
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffff11015663d4e RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88809500a4c0 R14: ffff8880ab31ea70 R15: 0000000000000001
FS:  0000000000f393c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b11b0 CR3: 00000000b53c7000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
 estimation_timer+0x2c/0x8b0 include/linux/spinlock.h:329
 call_timer_fn+0x177/0x700 kernel/time/timer.c:1338
 expire_timers+0x243/0x4e0 kernel/time/timer.c:1375
 __run_timers kernel/time/timer.c:1696 [inline]
 run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709
 __do_softirq+0x265/0x980 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x215/0x260 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:535 [inline]
 smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:192
Code: c0 58 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 91 87 d9 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 c6 6e 29 f9 65 8b 05 2f e4 e9 77 85 c0 74 02 5d
RSP: 0018:ffff8880b0befb10 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13e304b RBX: ffff88809500a4c0 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff88809500ad44
RBP: ffff8880ba12b040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba12b040
R13: ffff8880261e2100 R14: 0000000000000000 R15: 0000000000000000
 finish_lock_switch kernel/sched/core.c:2578 [inline]
 finish_task_switch+0x146/0x760 kernel/sched/core.c:2678
 context_switch kernel/sched/core.c:2831 [inline]
 __schedule+0x88f/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x264/0x6c0 kernel/time/hrtimer.c:1709
 hrtimer_nanosleep+0x24d/0x570 kernel/time/hrtimer.c:1763
 common_nsleep+0x23/0x30 kernel/time/posix-timers.c:1204
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1231 [inline]
 __se_sys_clock_nanosleep+0x261/0x360 kernel/time/posix-timers.c:1209
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x476a5a
Code: 83 ff 03 74 3b 48 83 ec 28 b8 fa ff ff ff 83 ff 02 49 89 ca 0f 44 f8 64 8b 04 25 18 00 00 00 85 c0 75 2d b8 e6 00 00 00 0f 05 <89> c2 f7 da 3d 00 f0 ff ff b8 00 00 00 00 0f 47 c2 48 83 c4 28 c3
RSP: 002b:00007ffd8e809470 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 00000000000cc712 RCX: 0000000000476a5a
RDX: 00007ffd8e8094b0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000007567 R08: 00007ffd8e8b9000 R09: 000000e1366e286d
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd8e8094ec
R13: 431bde82d7b634db R14: 00007ffd8e809500 R15: 0000000000400488