IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth3: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth5: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth7: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth9: link becomes ready INFO: task syz-executor1:29672 blocked for more than 140 seconds. Not tainted 4.20.0-rc3+ #203 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D22776 29672 6025 0x80000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 exp_funnel_lock kernel/rcu/tree_exp.h:319 [inline] _synchronize_rcu_expedited.constprop.58+0x8df/0x9d0 kernel/rcu/tree_exp.h:620 synchronize_rcu_expedited+0x27/0xa0 kernel/rcu/tree_exp.h:758 synchronize_net+0x3b/0x60 net/core/dev.c:9069 tipc_nametbl_stop+0x968/0xca0 net/tipc/name_table.c:797 tipc_exit_net+0x2d/0x40 net/tipc/core.c:103 ops_exit_list.isra.5+0xb0/0x160 net/core/net_namespace.c:153 setup_net+0x501/0x8d0 net/core/net_namespace.c:331 copy_net_ns+0x2b1/0x4a0 net/core/net_namespace.c:437 create_new_namespaces+0x6ad/0x900 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:206 ksys_unshare+0x79c/0x10b0 kernel/fork.c:2539 __do_sys_unshare kernel/fork.c:2607 [inline] __se_sys_unshare kernel/fork.c:2605 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2605 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: 83 c4 18 c3 e8 d8 64 00 00 48 8b 04 24 48 8b 4c 24 08 48 89 01 e8 d7 2d fc ff e8 22 7a fc ff b8 02 00 00 00 48 8d 0d aa 3c 0c <01> 87 01 8b 05 a2 3c 0c 01 83 f8 01 0f 85 8a 00 00 00 b8 01 00 00 RSP: 002b:00007f3b16ed6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b16ed76d4 R13: 00000000004c56df R14: 00000000004d96d0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1019: #0: 00000000b860deed (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 2 locks held by rsyslogd/5881: #0: 0000000090e432c2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 00000000b860deed (rcu_read_lock){....}, at: __debug_check_no_obj_freed lib/debugobjects.c:777 [inline] #1: 00000000b860deed (rcu_read_lock){....}, at: debug_check_no_obj_freed+0x17a/0x58d lib/debugobjects.c:818 2 locks held by getty/5971: #0: 000000002af1fd86 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000bcac24f0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5972: #0: 000000009dce68f6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000028969a97 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5973: #0: 00000000083773d9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ddb4517e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5974: #0: 0000000087e790b2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b3279c46 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5975: #0: 0000000055e31331 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a4f58002 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5976: #0: 00000000181e6444 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a4d88390 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5977: #0: 000000009962233f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000454b0061 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 1 lock held by syz-executor1/29672: #0: 00000000903b622b (pernet_ops_rwsem){++++}, at: copy_net_ns+0x28c/0x4a0 net/core/net_namespace.c:433 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1019 Comm: khungtaskd Not tainted 4.20.0-rc3+ #203 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57