------------[ cut here ]------------
WARNING: CPU: 1 PID: 3828 at net/ipv4/af_inet.c:167 inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3828 Comm: syz-executor247 Not tainted 4.9.124-g09eb2ba #35
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db307cc0 ffffffff81eb95e9 ffffffff83c48ac0 00000000ffffffff
 0000000000000000 0000000000000001 00000000000000a7 ffff8801db307d80
 ffffffff81423eb5 0000000041b58ab3 ffffffff843bb8e8 ffffffff81423cf6
Call Trace:
 <IRQ> [   27.908375]  [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [   27.908375]  [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81423eb5>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff814241a1>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff811383bc>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<ffffffff8342c878>] inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167
 [<ffffffff836c5839>] l2tp_tunnel_destruct+0x339/0x590 net/l2tp/l2tp_core.c:1329
 [<ffffffff830281f5>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff812899ee>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff812899ee>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff812899ee>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff812899ee>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff812899ee>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff83a085c0>] __do_softirq+0x210/0x940 kernel/softirq.c:288
 [<ffffffff8114d554>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff8114d554>] irq_exit+0x114/0x150 kernel/softirq.c:409
 [<ffffffff83a071a1>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff83a071a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:962
 [<ffffffff83a03330>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [   28.030532]  [<ffffffff8153f422>] ? kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547
 [<ffffffff8153ee57>] set_track mm/kasan/kasan.c:517 [inline]
 [<ffffffff8153ee57>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609
 [<ffffffff8153f422>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547
 [<ffffffff8153b332>] slab_post_alloc_hook mm/slab.h:417 [inline]
 [<ffffffff8153b332>] slab_alloc_node mm/slub.c:2715 [inline]
 [<ffffffff8153b332>] slab_alloc mm/slub.c:2723 [inline]
 [<ffffffff8153b332>] __kmalloc+0xe2/0x300 mm/slub.c:3737
 [<ffffffff8302517e>] kmalloc include/linux/slab.h:495 [inline]
 [<ffffffff8302517e>] sk_prot_alloc+0x17e/0x290 net/core/sock.c:1338
 [<ffffffff8302b9ba>] sk_alloc+0x3a/0x3a0 net/core/sock.c:1394
 [<ffffffff836cb213>] pppol2tp_create+0x33/0x1f0 net/l2tp/l2tp_ppp.c:534
 [<ffffffff829c3756>] pppox_create+0xf6/0x210 drivers/net/ppp/pppox.c:121
 [<ffffffff830204d1>] __sock_create+0x2f1/0x5f0 net/socket.c:1195
 [<ffffffff83020a00>] sock_create net/socket.c:1235 [inline]
 [<ffffffff83020a00>] SYSC_socket net/socket.c:1265 [inline]
 [<ffffffff83020a00>] SyS_socket+0xf0/0x1b0 net/socket.c:1245
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff83a030d0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..