IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
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 ffff8801d449aa00 by task syz-executor0/4493

CPU: 1 PID: 4493 Comm: syz-executor0 Not tainted 4.4.146-g1396226 #15
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 ee8684c87f8afb7a ffff8800b7547c20 ffffffff81e1292d
 ffffea0007512680 ffff8801d449aa00 0000000000000000 ffff8801d449aa00
 ffffffff82f1f7c0 ffff8800b7547c58 ffffffff81517f76 ffff8801d449aa00
Call Trace:
 [<ffffffff81e1292d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e1292d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81517f76>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81518295>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81518295>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fbd64>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff835acde2>] pppol2tp_session_destruct+0xf2/0x110 net/l2tp/l2tp_ppp.c:476
 [<ffffffff82f3484c>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82f34d0f>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f34f10>] sk_free+0x30/0x40 net/core/sock.c:1491
 [<ffffffff835adb9a>] sock_put include/net/sock.h:1639 [inline]
 [<ffffffff835adb9a>] pppol2tp_release+0x26a/0x310 net/l2tp/l2tp_ppp.c:518
 [<ffffffff82f1f696>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f7d6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff81525365>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815258a5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118e00f>] 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:253
 [<ffffffff8100708e>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff8100708e>] syscall_return_slowpath arch/x86/entry/common.c:349 [inline]
 [<ffffffff8100708e>] do_syscall_32_irqs_on arch/x86/entry/common.c:399 [inline]
 [<ffffffff8100708e>] do_fast_syscall_32+0x61e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838ca383>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 4494:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae33>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb117>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb117>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f7834>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff835a6439>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff835a6439>] kzalloc include/linux/slab.h:620 [inline]
 [<ffffffff835a6439>] l2tp_session_create+0x39/0x1030 net/l2tp/l2tp_core.c:1748
 [<ffffffff835ab140>] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725
 [<ffffffff82f240b8>] SYSC_connect+0x1b8/0x300 net/socket.c:1558
 [<ffffffff82f269f4>] SyS_connect+0x24/0x30 net/socket.c:1539
 [<ffffffff81006d94>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d94>] do_fast_syscall_32+0x324/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838ca383>] sysenter_flags_fixed+0xd/0x1a

Freed by task 4490:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae33>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb762>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb762>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f8c64>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f8c64>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f8c64>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f8c64>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff835a33a0>] l2tp_session_free+0x170/0x200 net/l2tp/l2tp_core.c:1676
 [<ffffffff835a5759>] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline]
 [<ffffffff835a5759>] l2tp_tunnel_closeall+0x2b9/0x350 net/l2tp/l2tp_core.c:1279
 [<ffffffff835a626b>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff83498271>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f34f8d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff83496f25>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832fe88f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff83421520>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<ffffffff82f1f696>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f7d6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff81525365>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815258a5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118e00f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff81137475>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff81137475>] do_exit+0x9e5/0x26b0 kernel/exit.c:755
 [<ffffffff8113d3b1>] do_group_exit+0x111/0x330 kernel/exit.c:885
 [<ffffffff811607ac>] get_signal+0x4ec/0x14b0 kernel/signal.c:2321
 [<ffffffff8100df4b>] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712
 [<ffffffff8100360a>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:249
 [<ffffffff81006363>] prepare_exit_to_usermode+0xe3/0x100 arch/x86/entry/common.c:284
 [<ffffffff838c95c8>] retint_user+0x8/0x3c

The buggy address belongs to the object at ffff8801d449aa00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8801d449aa00, ffff8801d449ac00)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.146-g1396226 #15
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84417840 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff81e30298>]  [<ffffffff81e30298>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
RSP: 0018:ffff8801db207d30  EFLAGS: 00010007
RAX: ffffed003b64339b RBX: ffff8801db219cc0 RCX: 0000000000000000
RDX: 000000001083e1e8 RSI: ffffffff81e3027c RDI: 00000000841f0f46
RBP: ffff8801db207d70 R08: 0000000000000096 R09: 0000000000000001
R10: 0000000000000000 R11: ffffffff84417840 R12: dffffc0000000000
R13: 00000000841f0f2e R14: 0000000ccf729300 R15: ffffffff8148f4a7
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6622fd7000 CR3: 00000001ccd84000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801db219cd8 ffff8801db219790 ffffed003b64339b ffff8801db219780
 ffff8801db219cc0 ffff8801db2196c0 0000000000000001 0000000000000000
 ffff8801db207da8 ffffffff8129d61f ffff8801db219cc0 0000000000000001
Call Trace:
 <IRQ> 
 [<ffffffff8129d61f>] enqueue_hrtimer+0x15f/0x440 kernel/time/hrtimer.c:893
 [<ffffffff812a0312>] __run_hrtimer kernel/time/hrtimer.c:1276 [inline]
 [<ffffffff812a0312>] __hrtimer_run_queues+0x6b2/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff812a1781>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810af3b4>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838cb69c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838ca5e0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff81025cd5>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81025cd5>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:432
 [<ffffffff81027be0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423
 [<ffffffff8121de97>] default_idle_call+0x57/0x70 kernel/sched/idle.c:93
 [<ffffffff8121e63f>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121e63f>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121e63f>] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301
 [<ffffffff838b5b71>] rest_init+0x188/0x18e init/main.c:410
 [<ffffffff84a4d8a1>] start_kernel+0x6b3/0x6e7 init/main.c:682
 [<ffffffff84a4c30f>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84a4c450>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185
Code: 00 00 4d 8b 2f 4d 85 ed 74 3d e8 34 35 52 ff 48 8b 45 d0 80 38 00 0f 85 96 01 00 00 49 8d 7d 18 4c 8b 73 18 48 89 fa 48 c1 ea 03 <42> 80 3c 22 00 0f 85 8a 01 00 00 4d 3b 75 18 7c a3 e8 02 35 52 
RIP  [<ffffffff81e30298>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
 RSP <ffff8801db207d30>
---[ end trace d254c3a975a1f84d ]---