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 l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
Read of size 4 at addr ffff8800b93dea00 by task syz-executor0/4222

CPU: 0 PID: 4222 Comm: syz-executor0 Not tainted 4.4.140-g789274d #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 fa5164b4085eca29 ffff8801c6b2fc78 ffffffff81e0e08d
 ffffea0002e4f780 ffff8800b93dea00 0000000000000000 ffff8800b93dea00
 ffffffff82f19f30 ffff8801c6b2fcb0 ffffffff81515a56 ffff8800b93dea00
Call Trace:
 [<ffffffff81e0e08d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e08d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81515a56>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81515d75>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81515d75>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f9844>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff8359adb4>] l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
 [<ffffffff835a78ef>] pppol2tp_release+0x1ff/0x310 net/l2tp/l2tp_ppp.c:509
 [<ffffffff82f19e06>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f19f46>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e45>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81523385>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118bdbf>] 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
 [<ffffffff838c40ea>] sysenter_flags_fixed+0xd/0x17

Allocated by task 4223:
 [<ffffffff81033e46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f8913>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f8bf7>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f8bf7>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f5314>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff835a01f9>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff835a01f9>] kzalloc include/linux/slab.h:620 [inline]
 [<ffffffff835a01f9>] l2tp_session_create+0x39/0x1030 net/l2tp/l2tp_core.c:1748
 [<ffffffff835a4f00>] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725
 [<ffffffff82f1e828>] SYSC_connect+0x1b8/0x300 net/socket.c:1557
 [<ffffffff82f21164>] 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
 [<ffffffff838c40ea>] sysenter_flags_fixed+0xd/0x17

Freed by task 4225:
 [<ffffffff81033e46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f8913>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f9242>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f9242>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f6744>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f6744>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f6744>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f6744>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff8359d160>] l2tp_session_free+0x170/0x200 net/l2tp/l2tp_core.c:1676
 [<ffffffff8359f519>] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline]
 [<ffffffff8359f519>] l2tp_tunnel_closeall+0x2b9/0x350 net/l2tp/l2tp_core.c:1279
 [<ffffffff835a002b>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff832cbd48>] udp_destroy_sock+0x118/0x1a0 net/ipv4/udp.c:2056
 [<ffffffff82f2f6dd>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff832c9d55>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832f8adf>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff82f19e06>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f19f46>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e45>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81523385>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118bdbf>] 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
 [<ffffffff838c40ea>] sysenter_flags_fixed+0xd/0x17

The buggy address belongs to the object at ffff8800b93dea00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8800b93dea00, ffff8800b93dec00)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at fffffffd4e90aec0
IP: [<ffffffff81224cf5>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
PGD 440f067 PUD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 3855 Comm: syz-execprog Not tainted 4.4.140-g789274d #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d92c8000 task.stack: ffff8801d8888000
RIP: 0010:[<ffffffff81224cf5>]  [<ffffffff81224cf5>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
RSP: 0018:ffff8801d888f890  EFLAGS: 00010046
RAX: 1ffffffff089500f RBX: 0000000000018528 RCX: ffffffff84a14ec0
RDX: fffffbffa9d215d8 RSI: fffffffd4e90aec0 RDI: ffffffff844a8078
RBP: ffff8801d888f8d0 R08: ffff8801d92c8950 R09: 0000000000000001
R10: 0000000000000001 R11: ffff8801d92c8000 R12: ffffffff844a7fa0
R13: dffffc0000000000 R14: 000000001ae45ce5 R15: ffffffffb93dec00
FS:  000000c4200283e8(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffd4e90aec0 CR3: 00000000b1538000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81224c00 0000000000000046 0000000000000003 ffff8800b9bdb060
 ffff8800b9bdb000 000000001ae45ce5 ffff8800b9bdb0b0 0000000000000000
 ffff8801d888f918 ffffffff811d9279 0000000000000005 ffff8801db21f4d8
Call Trace:
 [<ffffffff811d9279>] update_curr+0x2c9/0x6d0 kernel/sched/fair.c:882
 [<ffffffff811e447a>] enqueue_entity kernel/sched/fair.c:3512 [inline]
 [<ffffffff811e447a>] enqueue_task_fair+0x2fa/0x2790 kernel/sched/fair.c:4695
 [<ffffffff811bb95d>] enqueue_task kernel/sched/core.c:858 [inline]
 [<ffffffff811bb95d>] activate_task+0x14d/0x280 kernel/sched/core.c:874
 [<ffffffff811bc98f>] ttwu_activate kernel/sched/core.c:1736 [inline]
 [<ffffffff811bc98f>] ttwu_do_activate.constprop.109+0xbf/0x1e0 kernel/sched/core.c:1789
 [<ffffffff811bfba0>] ttwu_queue kernel/sched/core.c:1934 [inline]
 [<ffffffff811bfba0>] try_to_wake_up+0x660/0xf00 kernel/sched/core.c:2068
 [<ffffffff811c04fb>] wake_up_q+0xbb/0x130 kernel/sched/core.c:582
 [<ffffffff812ccabf>] futex_wake+0x3af/0x460 kernel/futex.c:1449
 [<ffffffff812d0a2d>] do_futex+0x26d/0x17f0 kernel/futex.c:3230
 [<ffffffff812d21a0>] SYSC_futex kernel/futex.c:3286 [inline]
 [<ffffffff812d21a0>] SyS_futex+0x1f0/0x300 kernel/futex.c:3254
 [<ffffffff838c27a5>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: 49 8d bc 24 d8 00 00 00 48 89 f8 48 c1 e8 03 42 80 3c 28 00 0f 85 c4 01 00 00 49 8b 9c 24 d8 00 00 00 80 3a 00 0f 85 8f 01 00 00 <4a> 03 1c f9 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 be 01 00 
RIP  [<ffffffff81224cf5>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
 RSP <ffff8801d888f890>
CR2: fffffffd4e90aec0
---[ end trace b3c173727b6c5f88 ]---