TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. INFO: task syz-executor6:23316 blocked for more than 120 seconds. Not tainted 4.18.0-rc3+ #128 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor6 D23888 23316 16942 0x80000006 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x87c/0x1ed0 kernel/sched/core.c:3504 schedule+0xfb/0x450 kernel/sched/core.c:3548 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1777 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x430/0x8d0 kernel/sched/completion.c:136 __wait_rcu_gp+0x257/0x350 kernel/rcu/update.c:366 synchronize_sched.part.63+0x104/0x120 kernel/rcu/tree.c:3097 synchronize_sched+0x76/0xf0 kernel/rcu/tree.c:3098 synchronize_rcu include/linux/rcupdate.h:94 [inline] namespace_unlock+0x1bb/0x210 fs/namespace.c:1424 drop_collected_mounts+0x85/0x90 fs/namespace.c:1848 put_mnt_ns+0x69/0x90 fs/namespace.c:3297 free_nsproxy+0x46/0x220 kernel/nsproxy.c:176 switch_task_namespaces+0xb8/0xd0 kernel/nsproxy.c:229 exit_task_namespaces+0x17/0x20 kernel/nsproxy.c:234 do_exit+0x1b03/0x2750 kernel/exit.c:864 do_group_exit+0x177/0x440 kernel/exit.c:968 get_signal+0x88e/0x1970 kernel/signal.c:2468 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455ab9 Code: e0 1f 48 89 04 24 e8 b6 6f fd ff e8 81 6a fd ff e8 5c 68 fd ff 48 8d 05 14 65 48 00 48 89 04 24 48 c7 44 24 08 1d 00 00 00 e8 <13> 5e fd ff 0f 0b e8 8c 44 00 00 e9 07 f0 ff ff cc cc cc cc cc cc RSP: 002b:00007fed542f3c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffff92 RBX: 00007fed542f46d4 RCX: 0000000000455ab9 RDX: 0000000000000000 RSI: 0000000020000c00 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c0faa R14: 00000000004d1058 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/899: #0: 0000000065a27e40 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4392: #0: 00000000a6b838f1 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4482: #0: 000000006a057dca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000cefef4c6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4483: #0: 000000004c0508fa (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008b6275ab (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4484: #0: 00000000f4526d8a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004b06387e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4485: #0: 00000000d368ed83 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000da49a92d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4486: #0: 00000000120dde16 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000006a4497a5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4487: #0: 000000006f444a7d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008fe34980 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4488: #0: 0000000095c0e4e6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000b5c42ec (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by kworker/0:0/24155: #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000aed38a62 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb44/0x1ba0 kernel/workqueue.c:2124 #1: 000000005151d87a ((work_completion)(&smc->connect_work)){+.+.}, at: process_one_work+0xb9b/0x1ba0 kernel/workqueue.c:2128 #2: 000000003d58c2c7 (sk_lock-AF_SMC){+.+.}, at: lock_sock include/net/sock.h:1474 [inline] #2: 000000003d58c2c7 (sk_lock-AF_SMC){+.+.}, at: smc_connect_work+0x32/0x3a0 net/smc/af_smc.c:593 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 899 Comm: khungtaskd Not tainted 4.18.0-rc3+ #128 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54