TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. INFO: task syz-executor1:9039 blocked for more than 140 seconds. Not tainted 4.19.0-rc6+ #47 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D17472 9039 5931 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 xlog_grant_head_wait+0x26b/0xf50 fs/xfs/xfs_log.c:263 xlog_grant_head_check+0x4e7/0x560 fs/xfs/xfs_log.c:325 xfs_log_reserve+0x3b6/0xd50 fs/xfs/xfs_log.c:454 xfs_log_write_unmount_record+0x336/0xc30 fs/xfs/xfs_log.c:854 xfs_log_unmount_write fs/xfs/xfs_log.c:953 [inline] xfs_log_quiesce+0x55c/0x660 fs/xfs/xfs_log.c:1020 xfs_log_unmount+0x22/0xb0 fs/xfs/xfs_log.c:1034 xfs_log_mount_cancel+0x44/0x60 fs/xfs/xfs_log.c:816 xfs_mountfs+0x147f/0x1ef0 fs/xfs/xfs_mount.c:1064 xfs_fs_fill_super+0xe8a/0x16f0 fs/xfs/xfs_super.c:1713 mount_bdev+0x30c/0x3e0 fs/super.c:1158 xfs_fs_mount+0x34/0x40 fs/xfs/xfs_super.c:1787 mount_fs+0xae/0x31d fs/super.c:1261 vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2457 [inline] do_mount+0x581/0x31f0 fs/namespace.c:2787 ksys_mount+0x12d/0x140 fs/namespace.c:3003 __do_sys_mount fs/namespace.c:3017 [inline] __se_sys_mount fs/namespace.c:3014 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3014 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459fea Code: 8d 05 1a 04 00 00 ff e0 48 81 f9 00 04 00 00 77 09 48 8d 05 b8 04 00 00 ff e0 48 81 f9 00 08 00 00 77 09 48 8d 05 56 05 00 00 e0 48 81 f9 00 10 00 00 77 09 48 8d 05 f4 05 00 00 ff e0 48 81 RSP: 002b:00007f31010b8a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f31010b8b30 RCX: 0000000000459fea RDX: 00007f31010b8ad0 RSI: 0000000020000100 RDI: 00007f31010b8af0 RBP: 0000000020000100 R08: 00007f31010b8b30 R09: 00007f31010b8ad0 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003 R13: 0000000000000000 R14: 00000000004d7ef0 R15: 00000000ffffffff INFO: lockdep is turned off. NMI backtrace for cpu 1 CPU: 1 PID: 982 Comm: khungtaskd Not tainted 4.19.0-rc6+ #47 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 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