IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
ip (4005) used greatest stack depth: 23600 bytes left
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
==================================================================
BUG: KASAN: use-after-free in pppol2tp_session_destruct+0xf2/0x110 net/l2tp/l2tp_ppp.c:476
Read of size 4 at addr ffff8801d4f9b400 by task syz-executor0/4264

CPU: 1 PID: 4264 Comm: syz-executor0 Not tainted 4.4.138-g07c0138 #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 b3e5512a738ae2c5 ffff8800b9bb7c20 ffffffff81e0ed0d
 ffffea000753e680 ffff8801d4f9b400 0000000000000000 ffff8801d4f9b400
 ffffffff82f1a2b0 ffff8800b9bb7c58 ffffffff81515a16 ffff8801d4f9b400
Call Trace:
 [<ffffffff81e0ed0d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0ed0d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81515a16>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81515d35>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81515d35>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f9804>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff835a6b22>] pppol2tp_session_destruct+0xf2/0x110 net/l2tp/l2tp_ppp.c:476
 [<ffffffff82f2f31c>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82f2f7df>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f2f9e0>] sk_free+0x30/0x40 net/core/sock.c:1491
 [<ffffffff835a78da>] sock_put include/net/sock.h:1639 [inline]
 [<ffffffff835a78da>] pppol2tp_release+0x26a/0x310 net/l2tp/l2tp_ppp.c:518
 [<ffffffff82f1a186>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f1a2c6>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e05>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81523345>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118bd7f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff8100362d>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100362d>] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252
 [<ffffffff81007090>] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline]
 [<ffffffff81007090>] syscall_return_slowpath arch/x86/entry/common.c:348 [inline]
 [<ffffffff81007090>] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline]
 [<ffffffff81007090>] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c406a>] sysenter_flags_fixed+0xd/0x17

Allocated by task 4264:
 [<ffffffff81033e46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f88d3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f8bb7>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f8bb7>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f52d4>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff835a0179>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff835a0179>] kzalloc include/linux/slab.h:620 [inline]
 [<ffffffff835a0179>] l2tp_session_create+0x39/0x1030 net/l2tp/l2tp_core.c:1748
 [<ffffffff835a4e80>] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725
 [<ffffffff82f1eba8>] SYSC_connect+0x1b8/0x300 net/socket.c:1557
 [<ffffffff82f214e4>] SyS_connect+0x24/0x30 net/socket.c:1538
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c406a>] sysenter_flags_fixed+0xd/0x17

Freed by task 4262:
 [<ffffffff81033e46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f88d3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f9202>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f9202>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f6704>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f6704>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f6704>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f6704>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff8359d0e0>] l2tp_session_free+0x170/0x200 net/l2tp/l2tp_core.c:1676
 [<ffffffff8359f499>] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline]
 [<ffffffff8359f499>] l2tp_tunnel_closeall+0x2b9/0x350 net/l2tp/l2tp_core.c:1279
 [<ffffffff8359ffab>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff832cbe58>] udp_destroy_sock+0x118/0x1a0 net/ipv4/udp.c:2056
 [<ffffffff82f2fa5d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff832c9e65>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832f8bef>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff82f1a186>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f1a2c6>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e05>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81523345>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118bd7f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff8100362d>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100362d>] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252
 [<ffffffff81007090>] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline]
 [<ffffffff81007090>] syscall_return_slowpath arch/x86/entry/common.c:348 [inline]
 [<ffffffff81007090>] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline]
 [<ffffffff81007090>] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c406a>] sysenter_flags_fixed+0xd/0x17

The buggy address belongs to the object at ffff8801d4f9b400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8801d4f9b400, ffff8801d4f9b600)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[   36.192629] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffffea000753e680
IP: [<ffffea000753e680>] 0xffffea000753e680
PGD 21f7fa067 PUD 21f7f9067 PMD 800000021e2001e3 
Oops: 0011 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3862 Comm: syz-executor0 Not tainted 4.4.138-g07c0138 #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c6830000 task.stack: ffff8801d97c0000
RIP: 0010:[<ffffea000753e680>]  [<ffffea000753e680>] 0xffffea000753e680
RSP: 0018:ffff8801db207708  EFLAGS: 00010246
RAX: ffff8801c6830000 RBX: dffffc0000000000 RCX: ffffea000753e680
RDX: ffff8801db207898 RSI: ffff8801da23fa00 RDI: ffffffff83aa9de0
RBP: ffff8801db207770 R08: 0000000000000000 R09: 0000000000000000
R10: ffffed003b447f47 R11: ffff8801da23fa3b R12: ffff8801db2077c8
R13: ffff8801db207898 R14: ffff8800b7402a88 R15: ffffed003b640ef9
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:0000000009265900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffffea000753e680 CR3: 00000001ce8d4000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff830c2372 ffffffff81286af9 ffff8801db20789c 1ffff1003b640ef9
 07ff8801da23fa00 ffffed003b640f13 ffffffff84918540 ffff8801da23fa00
 ffff8801da23fa00 ffff8801db207898 ffff8801da23fa00 ffffffff84917ac0
Call Trace:
 <IRQ> 
 [<ffffffff830c25b6>] nf_hook_slow+0x1b6/0x340 net/netfilter/core.c:306
 [<ffffffff83204826>] nf_hook_thresh include/linux/netfilter.h:187 [inline]
 [<ffffffff83204826>] NF_HOOK_THRESH include/linux/netfilter.h:224 [inline]
 [<ffffffff83204826>] NF_HOOK include/linux/netfilter.h:249 [inline]
 [<ffffffff83204826>] ip_rcv+0xbf6/0x1190 net/ipv4/ip_input.c:455
 [<ffffffff82f7eb06>] __netif_receive_skb_core+0x12d6/0x2940 net/core/dev.c:4019
 [<ffffffff82f801cb>] __netif_receive_skb+0x5b/0x1b0 net/core/dev.c:4054
 [<ffffffff82f80411>] netif_receive_skb_internal+0xf1/0x3a0 net/core/dev.c:4082
 [<ffffffff82f837bf>] napi_skb_finish net/core/dev.c:4417 [inline]
 [<ffffffff82f837bf>] napi_gro_receive+0x15f/0x420 net/core/dev.c:4446
 [<ffffffff8275e5b4>] receive_buf drivers/net/virtio_net.c:535 [inline]
 [<ffffffff8275e5b4>] virtnet_receive+0x774/0x1b70 drivers/net/virtio_net.c:755
 [<ffffffff8275f9d6>] virtnet_poll+0x26/0x140 drivers/net/virtio_net.c:773
 [<ffffffff82f81592>] napi_poll net/core/dev.c:4885 [inline]
 [<ffffffff82f81592>] net_rx_action+0x3a2/0xdb0 net/core/dev.c:4950
 [<ffffffff838c5bec>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273
 [<ffffffff8113f8ad>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff8113f8ad>] irq_exit+0x10d/0x140 kernel/softirq.c:391
 [<ffffffff838c5351>] exiting_irq arch/x86/include/asm/apic.h:653 [inline]
 [<ffffffff838c5351>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff838c4290>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff8125d51e>] vprintk_emit+0x51e/0x840 kernel/printk/printk.c:1832
 [<ffffffff8125d868>] vprintk+0x28/0x30 kernel/printk/printk.c:1843
 [<ffffffff8125d88d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1844
 [<ffffffff81415328>] printk+0xaf/0xd7 kernel/printk/printk.c:1922
 [<ffffffff81123a1b>] kasan_die_handler.cold.3+0x1d/0x22 arch/x86/mm/kasan_init_64.c:59
 [<ffffffff81194169>] notifier_call_chain+0xb9/0x1e0 kernel/notifier.c:93
 [<ffffffff8119577f>] __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
 [<ffffffff8119577f>] atomic_notifier_call_chain+0x7f/0x140 kernel/notifier.c:193
 [<ffffffff8119591f>] notify_die+0xdf/0x160 kernel/notifier.c:549
 [<ffffffff8101103a>] do_general_protection+0x20a/0x2b0 arch/x86/kernel/traps.c:461
 [<ffffffff838c3aa8>] general_protection+0x28/0x30 arch/x86/entry/entry_64.S:1036
 [<ffffffff81c6a233>] selinux_task_wait+0x23/0x30 security/selinux/hooks.c:3763
 [<ffffffff81c4f423>] security_task_wait+0x73/0xb0 security/security.c:986
 [<ffffffff81137228>] wait_consider_task+0x298/0x3600 kernel/exit.c:1330
 [<ffffffff8113a8f4>] do_wait_thread kernel/exit.c:1443 [inline]
 [<ffffffff8113a8f4>] do_wait+0x364/0xa30 kernel/exit.c:1514
 [<ffffffff8113b86b>] SYSC_wait4 kernel/exit.c:1645 [inline]
 [<ffffffff8113b86b>] SyS_wait4+0x12b/0x1f0 kernel/exit.c:1610
 [<ffffffff812f61a7>] C_SYSC_wait4+0x237/0x280 kernel/compat.c:543
 [<ffffffff812f655c>] compat_SyS_wait4+0x2c/0x40 kernel/compat.c:536
 [<ffffffff81115425>] sys32_waitpid+0x25/0x30 arch/x86/ia32/sys_ia32.c:172
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c406a>] sysenter_flags_fixed+0xd/0x17
Code: 00 00 00 49 00 49 00 01 00 00 00 80 d7 e4 02 00 ea ff ff 0e 00 00 00 1e 00 00 00 40 eb 00 da 01 88 ff ff 00 00 00 00 00 00 00 00 <80> 40 00 00 00 00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 
RIP  [<ffffea000753e680>] 0xffffea000753e680
 RSP <ffff8801db207708>
CR2: ffffea000753e680
---[ end trace dead20318357e856 ]---