IPVS: sync thread started: state = BACKUP, mcast_ifn = ip_vti0, syncid = 0, id = 0 IPVS: stopping backup sync thread 30883 ... INFO: task syz-executor4:30882 blocked for more than 120 seconds. Not tainted 4.16.0+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24200 30882 4531 0x00000004 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 schedule_timeout+0x1b5/0x240 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+0x3e7/0x870 kernel/sched/completion.c:136 kthread_stop+0x183/0x8e0 kernel/kthread.c:530 stop_sync_thread.cold.8+0x277/0x398 net/netfilter/ipvs/ip_vs_sync.c:1996 do_ip_vs_set_ctl+0x36c/0x1d30 net/netfilter/ipvs/ip_vs_ctl.c:2394 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x7d/0xd0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0xd8/0xf0 net/ipv4/ip_sockglue.c:1253 tcp_setsockopt+0x93/0xe0 net/ipv4/tcp.c:2888 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3039 smc_setsockopt+0xc7/0x120 net/smc/af_smc.c:1289 __sys_setsockopt+0x1bd/0x390 net/socket.c:1903 SYSC_setsockopt net/socket.c:1914 [inline] SyS_setsockopt+0x34/0x50 net/socket.c:1911 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x455319 RSP: 002b:00007f7f6f316c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f7f6f3176d4 RCX: 0000000000455319 RDX: 000000000000048c RSI: 0000000000000000 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000521 R14: 00000000006fabb8 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/888: #0: 00000000cab58948 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000cab58948 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 000000009a79fd1a (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by getty/4453: #0: 000000007a03f17c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c5e3f5e1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4454: #0: 00000000c04d23ca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000068c02419 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4455: #0: 0000000007d4be81 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004c2754fd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4456: #0: 00000000f630a047 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000067578f09 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4457: #0: 00000000e007b44b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a85ad739 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4458: #0: 0000000076d51d08 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000e516e907 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4459: #0: 00000000b46630b3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000025ffc28c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 3 locks held by kworker/0:3/4921: #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000008f84e1a0 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 000000005bfbbecd ((addr_chk_work).work){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 #2: 0000000081fa00d7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 1 lock held by syz-executor4/30882: #0: 0000000037d46932 (ipvs->sync_mutex){+.+.}, at: do_ip_vs_set_ctl+0x339/0x1d30 net/netfilter/ipvs/ip_vs_ctl.c:2393 2 locks held by syz-executor4/30888: #0: 0000000081fa00d7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: 0000000037d46932 (ipvs->sync_mutex){+.+.}, at: do_ip_vs_set_ctl+0x562/0x1d30 net/netfilter/ipvs/ip_vs_ctl.c:2388 1 lock held by ipvs-b:5:0/30883: #0: 0000000081fa00d7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 888 Comm: khungtaskd Not tainted 4.16.0+ #2 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+0x1b9/0x294 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_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0+ #2 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:reschedule_interrupt+0x0/0x20 arch/x86/entry/entry_64.S:885 RSP: 0018:ffffffff88a07b98 EFLAGS: 00000082 RAX: dffffc0000000000 RBX: 1ffffffff1140f7b RCX: 0000000000000000 RDX: 1ffffffff11630f0 RSI: 0000000000000001 RDI: ffffffff88b18780 RBP: ffffffff88a07bc0 R08: ffffed003b6046c3 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff88a07c78 R14: ffffffff8958d7e0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001486000 CR3: 00000001b47d8000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0xc2/0x440 arch/x86/kernel/process.c:354 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:345 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x395/0x560 kernel/sched/idle.c:262 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:368 rest_init+0xe1/0xe4 init/main.c:441 start_kernel+0x906/0x92d init/main.c:737 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:443 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:424 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242 Code: 90 66 2e 0f 1f 84 00 00 00 00 00 68 03 ff ff ff e8 d6 ef ff ff e8 11 2c 00 00 e9 cb f0 ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 <68> 02 ff ff ff e8 b6 ef ff ff e8 91 25 00 00 e9 ab f0 ff ff 66