INFO: task can't die in irqentry_exit (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    14240d4c Add linux-next specific files for 20201210
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=137b0f9b500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6dbe20fdaa5aaebe
dashboard link: https://syzkaller.appspot.com/bug?extid=b3c4057ecb552e754f4a
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=176d1287500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1236046b500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b3c4057ecb552e754f4a@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task syz-executor349:9910 can't die for more than 143 seconds.
task:syz-executor349 state:R  running task     stack:27536 pid: 9910 ppid:  8512 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4325 [inline]
 __schedule+0x8eb/0x21b0 kernel/sched/core.c:5076
 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:5338
 irqentry_exit_cond_resched kernel/entry/common.c:393 [inline]
 irqentry_exit_cond_resched kernel/entry/common.c:385 [inline]
 irqentry_exit+0x7a/0xa0 kernel/entry/common.c:423
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5440 [inline]
RIP: 0010:lock_acquire+0x2c7/0x750 kernel/locking/lockdep.c:5402
Code: 48 c7 c7 00 9c 6b 89 48 83 c4 20 e8 83 49 be 07 b8 ff ff ff ff 65 0f c1 05 c6 e3 a9 7e 83 f8 01 0f 85 40 03 00 00 ff 34 24 9d <e9> 3a fe ff ff 65 ff 05 2d d2 a9 7e 48 8b 05 a6 51 11 0c e8 a1 3e
RSP: 0018:ffffc9000a90f7c8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff92001521efb RCX: 0000000000000001
RDX: 1ffff110053f47f1 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8f4fe767
R10: fffffbfff1e9fcec R11: 0000000000000000 R12: 0000000000000002
R13: ffffffff8b78f120 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:255 [inline]
 rcu_read_lock include/linux/rcupdate.h:644 [inline]
 inet_twsk_purge+0x112/0x810 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190
 setup_net+0x508/0x850 net/core/net_namespace.c:365
 copy_net_ns+0x376/0x7b0 net/core/net_namespace.c:483
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x3e5/0x4d0 kernel/nsproxy.c:179
 copy_process+0x2aa7/0x6fe0 kernel/fork.c:2103
 kernel_clone+0xe7/0xad0 kernel/fork.c:2465
 __do_sys_clone+0xc8/0x110 kernel/fork.c:2582
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x44c9c9
RSP: 002b:00007f1b22b4fce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00000000006e3c68 RCX: 000000000044c9c9
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 00000000e1004d7c
RBP: 00000000006e3c60 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e3c6c
R13: 00007fffa37c4aef R14: 00007f1b22b509c0 R15: 0000000000000001

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888140baf138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x871/0x1630 kernel/workqueue.c:2246
 #1: ffffc90000ce7da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1630 kernel/workqueue.c:2250
 #2: ffffffff8d0bcb50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:566
 #3: ffffffff8b799728 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #3: ffffffff8b799728 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4ff/0x620 kernel/rcu/tree_exp.h:836
1 lock held by khungtaskd/1661:
 #0: ffffffff8b78f120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x28c kernel/locking/lockdep.c:6254
2 locks held by kworker/0:3/3202:
1 lock held by in:imklog/8197:
 #0: ffff888018541c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:923
2 locks held by kworker/0:2/8489:
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff88801087c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x871/0x1630 kernel/workqueue.c:2246
 #1: ffffc9000178fda8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1630 kernel/workqueue.c:2250
2 locks held by syz-executor349/9910:
2 locks held by syz-executor349/9935:
2 locks held by syz-executor349/10031:
1 lock held by syz-executor349/10264:
2 locks held by syz-executor349/10269:
 #0: ffffffff8d0bcb50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x352/0x7b0 net/core/net_namespace.c:479
 #1: ffffffff8d0d76e8 (rtnl_mutex){+.+.}-{3:3}, at: ip_fib_net_exit+0x1b/0x2b0 net/ipv4/fib_frontend.c:1544
2 locks held by syz-executor349/10397:
3 locks held by syz-executor349/10412:

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