IPVS: stopping backup sync thread 29422 ... INFO: task syz-executor7:29404 blocked for more than 120 seconds. Not tainted 4.9.99-g74fa0af4 #27 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D28328 29404 3866 0x00000004 ffff8801a92d6000 ffff8801cc87e4c0 ffff8801cc87e4c0 ffff8801d4f5e000 ffff8801db321b98 ffff8801cd82f7b0 ffffffff839e377d 0000000000002d1c ffff8801a92d6908 ffffffff85597ad0 00ff8801a92d6910 ffff8801db322468 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768 [] do_wait_for_common kernel/sched/completion.c:75 [inline] [] __wait_for_common kernel/sched/completion.c:93 [inline] [] wait_for_common kernel/sched/completion.c:101 [inline] [] wait_for_completion+0x203/0x2e0 kernel/sched/completion.c:122 [] kthread_stop+0xa6/0x5d0 kernel/kthread.c:513 [] stop_sync_thread.cold.9+0x260/0x363 net/netfilter/ipvs/ip_vs_sync.c:1998 [] do_ip_vs_set_ctl+0x654/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2403 [] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline] [] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114 [] ip_setsockopt+0x9a/0xb0 net/ipv4/ip_sockglue.c:1249 [] tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2757 [] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 [] SYSC_setsockopt net/socket.c:1772 [inline] [] SyS_setsockopt+0x166/0x260 net/socket.c:1751 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 3 locks held by kworker/1:1/24: #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] work_static include/linux/workqueue.h:186 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085 #1: ((addr_chk_work).work){+.+...}, at: [] process_one_work+0x728/0x1500 kernel/workqueue.c:2089 #2: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/3776: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133 1 lock held by syz-executor7/29404: #0: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x645/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2402 2 locks held by syz-executor7/29423: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #1: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x90d/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2397 1 lock held by ipvs-b:4:0/29422: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.99-g74fa0af4 #27 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8dcfd08 ffffffff81eb0f09 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810b7da0 ffff8801d8dcfd40 ffffffff81ebc207 0000000000000000 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff839f3286