TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. BUG: sleeping function called from invalid context at net/core/sock.c:2502 in_atomic(): 1, irqs_disabled(): 0, pid: 3, name: ksoftirqd/0 1 lock held by ksoftirqd/0/3: #0: (rcu_callback){......}, at: [] __rcu_reclaim kernel/rcu/rcu.h:108 [inline] #0: (rcu_callback){......}, at: [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] #0: (rcu_callback){......}, at: [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] #0: (rcu_callback){......}, at: [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] #0: (rcu_callback){......}, at: [] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037 Preemption disabled at:[ 274.752781] [] __do_softirq+0xdd/0x940 kernel/softirq.c:265 CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.9.124-g09eb2ba #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d99efa60 ffffffff81eb95e9 ffffffff83a0848d 0000000000000000 0000000000000100 ffff8801d99bb000 ffff8801d99bb000 ffff8801d99efa98 ffffffff81426851 ffff8801d99bb000 ffffffff840f88a0 00000000000009c6 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] ___might_sleep.cold.123+0x1bc/0x1f5 kernel/sched/core.c:7988 [] __might_sleep+0x95/0x1a0 kernel/sched/core.c:7945 [] lock_sock_nested+0x34/0x120 net/core/sock.c:2502 [] lock_sock include/net/sock.h:1404 [inline] [] inet_shutdown+0x69/0x360 net/ipv4/af_inet.c:823 [] pppol2tp_session_close+0xa0/0xe0 net/l2tp/l2tp_ppp.c:441 [] l2tp_tunnel_closeall+0x231/0x350 net/l2tp/l2tp_core.c:1368 [] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] __rcu_reclaim kernel/rcu/rcu.h:118 [inline] [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] [] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037 [] __do_softirq+0x210/0x940 kernel/softirq.c:288 [] run_ksoftirqd+0x30/0x60 kernel/softirq.c:680 [] smpboot_thread_fn+0x5c9/0x900 kernel/smpboot.c:163 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 ================================= [ INFO: inconsistent lock state ] 4.9.124-g09eb2ba #35 Tainted: G W --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. ksoftirqd/0/3 [HC0[0]:SC1[3]:HE1:SE0] takes: (sk_lock-AF_PPPOX){+.?.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] (sk_lock-AF_PPPOX){+.?.+.}, at: [] inet_shutdown+0x69/0x360 net/ipv4/af_inet.c:823 mark_held_locks+0xc7/0x130 kernel/locking/lockdep.c:2660 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2689 [inline] trace_hardirqs_on_caller+0x38b/0x590 kernel/locking/lockdep.c:2736 trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2743 __local_bh_enable_ip+0x6a/0xd0 kernel/softirq.c:190 local_bh_enable include/linux/bottom_half.h:31 [inline] lock_sock_nested+0xdc/0x120 net/core/sock.c:2512 lock_sock include/net/sock.h:1404 [inline] pppol2tp_connect+0xd9/0x18f0 net/l2tp/l2tp_ppp.c:590 SYSC_connect+0x1b8/0x300 net/socket.c:1575 SyS_connect+0x24/0x30 net/socket.c:1556 do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387 entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 irq event stamp: 7068976 hardirqs last enabled at (7068976): [] restore_regs_and_iret+0x0/0x1d hardirqs last disabled at (7068975): [] common_interrupt+0x9b/0xa0 arch/x86/entry/entry_64.S:461 softirqs last enabled at (7068014): [] __do_softirq+0x475/0x940 kernel/softirq.c:314 softirqs last disabled at (7068017): [] run_ksoftirqd+0x30/0x60 kernel/softirq.c:680 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_PPPOX); lock(sk_lock-AF_PPPOX); *** DEADLOCK *** 1 lock held by ksoftirqd/0/3: #0: (rcu_callback){......}, at: [] __rcu_reclaim kernel/rcu/rcu.h:108 [inline] #0: (rcu_callback){......}, at: [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] #0: (rcu_callback){......}, at: [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] #0: (rcu_callback){......}, at: [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] #0: (rcu_callback){......}, at: [] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037 stack backtrace: CPU: 0 PID: 3 Comm: ksoftirqd/0 Tainted: G W 4.9.124-g09eb2ba #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d99ef7d8 ffffffff81eb95e9 ffff8801d99bb000 ffffffff8560f080 ffff8801d99bb8f0 ffff8801d99bb910 0000000000000000 ffff8801d99ef848 ffffffff81429ccd 0000000000000003 0000000000000001 ffff880100000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_usage_bug.cold.57+0x327/0x421 kernel/locking/lockdep.c:2387 [] valid_state kernel/locking/lockdep.c:2400 [inline] [] mark_lock_irq kernel/locking/lockdep.c:2602 [inline] [] mark_lock+0xcc6/0x1280 kernel/locking/lockdep.c:3065 [] mark_irqflags kernel/locking/lockdep.c:2923 [inline] [] __lock_acquire+0xd40/0x4070 kernel/locking/lockdep.c:3302 [] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 [] lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 [] lock_sock include/net/sock.h:1404 [inline] [] inet_shutdown+0x69/0x360 net/ipv4/af_inet.c:823 [] pppol2tp_session_close+0xa0/0xe0 net/l2tp/l2tp_ppp.c:441 [] l2tp_tunnel_closeall+0x231/0x350 net/l2tp/l2tp_core.c:1368 [] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] __rcu_reclaim kernel/rcu/rcu.h:118 [inline] [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] [] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037 [] __do_softirq+0x210/0x940 kernel/softirq.c:288 [] run_ksoftirqd+0x30/0x60 kernel/softirq.c:680 [] smpboot_thread_fn+0x5c9/0x900 kernel/smpboot.c:163 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 PGD 1c9de9067 [ 275.725049] PUD 1d4664067 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 16171 Comm: syz-executor5 Tainted: G W 4.9.124-g09eb2ba #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801baf2b000 task.stack: ffff8801b59f0000 RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 RSP: 0018:ffff8801b59f7c88 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff8801b7621900 RCX: 0000000000000000 RDX: 1ffff100390f53a0 RSI: ffffffff836c4711 RDI: ffff8801c87a9d00 RBP: ffff8801b59f7ca8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c87a9b80 R13: ffff8801b7621908 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000088fe900 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000001b6cd2000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801a5297700 ffff8801b7621900 ffff8801a5297ad0 ffff8801a52979d8 ffff8801b59f7cd0 ffffffff836cc022 ffff8801a5297b40 ffff8801a5297700 ffffffff836cbf50 ffff8801b59f7d08 ffffffff830281f5 ffff8801a5297b40 Call Trace: [] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:297 [inline] [] pppol2tp_session_destruct+0xd2/0x110 net/l2tp/l2tp_ppp.c:460 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] sk_destruct+0x63/0x80 net/core/sock.c:1463 [] __sk_free+0x4f/0x220 net/core/sock.c:1471 [] sk_free+0x2b/0x40 net/core/sock.c:1482 [] sock_put include/net/sock.h:1588 [inline] [] pppol2tp_release+0x239/0x2e0 net/l2tp/l2tp_ppp.c:501 [] __sock_release+0xd7/0x260 net/socket.c:605 [] sock_close+0x19/0x20 net/socket.c:1059 [] __fput+0x263/0x700 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10c/0x180 kernel/task_work.c:116 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161 [] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:260 [inline] [] do_syscall_32_irqs_on arch/x86/entry/common.c:331 [inline] [] do_fast_syscall_32+0x5c3/0x870 arch/x86/entry/common.c:387 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 Code: 49 8d bc 24 80 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c6 00 00 00 4d 8b b4 24 80 01 00 00 41 ff 8e 80 00 00 00 74 69 e8 a5 c5 c9 fd 4c 89 ea 48 b8 00 RIP [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1765 RSP CR2: 0000000000000080 ---[ end trace e034c550f52b3dd7 ]---