kworker/dying (7998) used greatest stack depth: 7952 bytes left INFO: task syz-executor1:4291 blocked for more than 120 seconds. Not tainted 4.16.0-rc2+ #249 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D20400 4291 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x905/0x2070 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3557 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 xt_request_find_table_lock+0x28/0xc0 net/netfilter/x_tables.c:1087 get_info+0x154/0x690 net/ipv6/netfilter/ip6_tables.c:993 do_ip6t_get_ctl+0x159/0xaf0 net/ipv6/netfilter/ip6_tables.c:1714 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122 ipv6_getsockopt+0x1d5/0x2c0 net/ipv6/ipv6_sockglue.c:1370 tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3332 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2938 SYSC_getsockopt net/socket.c:1881 [inline] SyS_getsockopt+0x178/0x340 net/socket.c:1863 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45683a RSP: 002b:0000000000a3e3b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 0000000000a3e3e0 RCX: 000000000045683a RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000013 RBP: 00000000006fd8e0 R08: 0000000000a3e3dc R09: 0000000000004000 R10: 0000000000a3e3e0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000013 R14: 0000000000000029 R15: 00000000006fb720 Showing all locks held in the system: 2 locks held by khungtaskd/799: #0: (rcu_read_lock){....}, at: [<000000006a1cb065>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000006a1cb065>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000dfe8b4ef>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4096: #0: (&f->f_pos_lock){+.+.}, at: [<000000005b970d2c>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4218: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4219: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4220: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4221: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4222: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4223: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4224: #0: (&tty->ldisc_sem){++++}, at: [<00000000e0e4ebb9>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a24c5a4d>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor1/4291: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor0/4292: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor2/4297: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor5/4299: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor7/4300: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 1 lock held by syz-executor3/4301: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 2 locks held by syz-executor4/4303: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 #1: (hashlimit_mutex){+.+.}, at: [<000000005b095cbc>] htable_put+0x73/0x300 net/netfilter/xt_hashlimit.c:439 1 lock held by syz-executor6/4304: #0: (&xt[i].mutex){+.+.}, at: [<00000000cd35b585>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1040 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 799 Comm: khungtaskd Not tainted 4.16.0-rc2+ #249 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 4.16.0-rc2+ #249 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_power_efficient htable_gc RIP: 0010:mark_lock+0x1d8/0x1430 kernel/locking/lockdep.c:3114 RSP: 0018:ffff8801d945f2b8 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 0000000000000002 RCX: 1ffffffff102cb06 RDX: ffff8801d9450ec0 RSI: 1ffff1003b28a1d8 RDI: ffffffff88165830 RBP: ffff8801d945f3e0 R08: 1ffff1003b28be5b R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d9450ea0 R13: 0000000000000004 R14: 0000000000000001 R15: 1ffff1003b28be5b FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001cd1000 CR3: 0000000006e22005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_held_locks+0xaf/0x100 kernel/locking/lockdep.c:2807 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2828 [inline] trace_hardirqs_on_caller+0x19e/0x5c0 kernel/locking/lockdep.c:2883 trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2890 __local_bh_enable_ip+0x121/0x230 kernel/softirq.c:187 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_bh+0x30/0x40 kernel/locking/spinlock.c:200 spin_unlock_bh include/linux/spinlock.h:355 [inline] htable_selective_cleanup+0x289/0x3d0 net/netfilter/xt_hashlimit.c:380 htable_gc+0x2e/0xc0 net/netfilter/xt_hashlimit.c:391 process_one_work+0xbbf/0x1af0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407 Code: c1 e9 03 80 3c 01 00 0f 85 0e 11 00 00 4d 85 6e 30 74 73 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 c7 04 07 00 00 00 00 <4a> c7 44 38 08 00 00 00 00 4a c7 44 38 10 00 00 00 00 42 c7 44