INFO: task syz-executor3:7139 blocked for more than 120 seconds. Not tainted 4.9.84-ge7f51a5 #45 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D29072 7139 3883 0x00000004 ffff8801cc999800 0000000000000000 ffff8801d0561a40 ffff8801cdf1e000 ffff8801db221b98 ffff8801cbf8fa70 ffffffff838a438b ffff8801cc999800 ffffffff8114529a 00fffc0000000000 ffff8801db222468 ffff8801db222490 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3550 [] __lock_sock+0x13c/0x260 net/core/sock.c:2035 [] lock_sock_nested+0xf6/0x120 net/core/sock.c:2505 [] lock_sock include/net/sock.h:1404 [inline] [] ipv6_getorigdst+0x136/0x610 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:238 [] nf_sockopt net/netfilter/nf_sockopt.c:103 [inline] [] nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:121 [] ipv6_getsockopt+0x1ce/0x250 net/ipv6/ipv6_sockglue.c:1347 [] tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3103 [] sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2665 [] SYSC_getsockopt net/socket.c:1803 [inline] [] SyS_getsockopt+0x14a/0x230 net/socket.c:1785 [] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x47/0xc5 Showing all locks held in the system: 2 locks held by khungtaskd/515: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x125/0xa70 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336 2 locks held by getty/3781: #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+0x1f4/0x16c0 drivers/tty/n_tty.c:2133 1 lock held by syz-executor3/7139: #0: (sk_lock-AF_INET6){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] #0: (sk_lock-AF_INET6){+.+.+.}, at: [] ipv6_getsockopt+0x1b3/0x250 net/ipv6/ipv6_sockglue.c:1346 1 lock held by syz-executor3/7160: #0: (sk_lock-AF_INET6){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] #0: (sk_lock-AF_INET6){+.+.+.}, at: [] ipv6_getsockopt+0x1b3/0x250 net/ipv6/ipv6_sockglue.c:1346 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 515 Comm: khungtaskd Not tainted 4.9.84-ge7f51a5 #45 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d859fd00 ffffffff81d956b9 0000000000000000 0000000000000001 0000000000000001 0000000000000001 ffffffff810bb190 ffff8801d859fd38 ffffffff81da07dd 0000000000000001 0000000000000000 ffff8801cdf1b418 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x117/0x190 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+0x6f0/0xa70 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:361 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff838b4076