==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092
Read of size 8 at addr ffff8800b23c4d20 by task syz-executor6/11124

CPU: 1 PID: 11124 Comm: syz-executor6 Not tainted 4.4.147-ga5fc665 #80
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 b2bdaaf2b799a6ac ffff8801cc01fa70 ffffffff81e12a4d
 ffffea0002c8f000 ffff8800b23c4d20 0000000000000000 ffff8800b23c4d20
 0000000000000000 ffff8801cc01faa8 ffffffff81517fd6 ffff8800b23c4d20
Call Trace:
 [<ffffffff81e12a4d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e12a4d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81517fd6>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff815182f5>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff815182f5>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fbde4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff81234f26>] __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092
 [<ffffffff81237d0e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff838c7eca>] __raw_spin_lock_bh include/linux/spinlock_api_smp.h:137 [inline]
 [<ffffffff838c7eca>] _raw_spin_lock_bh+0x3a/0x50 kernel/locking/spinlock.c:175
 [<ffffffff82f2c093>] spin_lock_bh include/linux/spinlock.h:307 [inline]
 [<ffffffff82f2c093>] lock_sock_nested+0x43/0x120 net/core/sock.c:2451
 [<ffffffff835adb90>] lock_sock include/net/sock.h:1493 [inline]
 [<ffffffff835adb90>] pppol2tp_release+0x50/0x310 net/l2tp/l2tp_ppp.c:493
 [<ffffffff82f1f876>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f9b6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff815253c5>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81525905>] ____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
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:349
 [<ffffffff838c8df5>] int_ret_from_sys_call+0x25/0xa3

Allocated by task 11134:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae93>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb177>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb177>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f7894>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff82f2af54>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff82f2af54>] sk_prot_alloc+0x204/0x300 net/core/sock.c:1354
 [<ffffffff82f3092a>] sk_alloc+0x3a/0x3a0 net/core/sock.c:1419
 [<ffffffff835a9ab3>] pppol2tp_create+0x33/0x1f0 net/l2tp/l2tp_ppp.c:551
 [<ffffffff828f68c6>] pppox_create+0xf6/0x200 drivers/net/ppp/pppox.c:121
 [<ffffffff82f25da0>] __sock_create+0x2f0/0x5f0 net/socket.c:1178
 [<ffffffff82f262d0>] sock_create net/socket.c:1218 [inline]
 [<ffffffff82f262d0>] SYSC_socket net/socket.c:1248 [inline]
 [<ffffffff82f262d0>] SyS_socket+0xf0/0x1b0 net/socket.c:1228
 [<ffffffff838c8c65>] entry_SYSCALL_64_fastpath+0x22/0x9e

Freed by task 11124:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae93>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb7c2>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb7c2>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f8cc4>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f8cc4>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f8cc4>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f8cc4>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff82f34de7>] sk_prot_free net/core/sock.c:1391 [inline]
 [<ffffffff82f34de7>] sk_destruct+0x407/0x4c0 net/core/sock.c:1472
 [<ffffffff82f34eef>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f350f0>] sk_free+0x30/0x40 net/core/sock.c:1491
 [<ffffffff835ad06f>] sock_put include/net/sock.h:1639 [inline]
 [<ffffffff835ad06f>] pppol2tp_session_sock_put+0x5f/0x70 net/l2tp/l2tp_ppp.c:286
 [<ffffffff835a58ec>] l2tp_tunnel_closeall+0x23c/0x350 net/l2tp/l2tp_core.c:1277
 [<ffffffff835a647b>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff83498481>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f3516d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff83497135>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832fea9f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff83421730>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<ffffffff82f1f876>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f9b6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff815253c5>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81525905>] ____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
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:349
 [<ffffffff838c8df5>] int_ret_from_sys_call+0x25/0xa3

The buggy address belongs to the object at ffff8800b23c4c80
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 160 bytes inside of
 2048-byte region [ffff8800b23c4c80, ffff8800b23c5480)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at fffffffde4ad6880
IP: [<ffffffff81226f45>] 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: 0 PID: 3794 Comm: syz-executor4 Not tainted 4.4.147-ga5fc665 #80
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9a86000 task.stack: ffff8801d6c50000
RIP: 0010:[<ffffffff81226f45>]  [<ffffffff81226f45>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
RSP: 0018:ffff8801d6c578b8  EFLAGS: 00010046
RAX: 1ffffffff089521f RBX: 00000000000185a8 RCX: ffffffff84a16600
RDX: fffffbffbc95ad10 RSI: fffffffde4ad6880 RDI: ffffffff844a90f8
RBP: ffff8801d6c578f8 R08: ffff8801d9a869c8 R09: 0000000000000001
R10: 0000000000000001 R11: ffff8801d9a86000 R12: ffffffff844a9020
R13: dffffc0000000000 R14: 000000001b9af0cb R15: ffffffffcc018050
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffde4ad6880 CR3: 000000000440c000 CR4: 00000000001606f0
Stack:
 ffffffff81226e50 0000000000000046 0000000000000003 ffff8800ae6ab060
 ffff8800ae6ab000 000000001b9af0cb ffff8800ae6ab0b0 0000000000000000
 ffff8801d6c57940 ffffffff811db4c9 0000000000000005 ffff8801db31f558
Call Trace:
 [<ffffffff811db4c9>] update_curr+0x2c9/0x6d0 kernel/sched/fair.c:882
 [<ffffffff811e66ca>] enqueue_entity kernel/sched/fair.c:3512 [inline]
 [<ffffffff811e66ca>] enqueue_task_fair+0x2fa/0x2790 kernel/sched/fair.c:4695
 [<ffffffff811bdbad>] enqueue_task kernel/sched/core.c:858 [inline]
 [<ffffffff811bdbad>] activate_task+0x14d/0x280 kernel/sched/core.c:874
 [<ffffffff811bebdf>] ttwu_activate kernel/sched/core.c:1736 [inline]
 [<ffffffff811bebdf>] ttwu_do_activate.constprop.109+0xbf/0x1e0 kernel/sched/core.c:1789
 [<ffffffff811c1df0>] ttwu_queue kernel/sched/core.c:1934 [inline]
 [<ffffffff811c1df0>] try_to_wake_up+0x660/0xf00 kernel/sched/core.c:2068
 [<ffffffff811c4940>] wake_up_state+0x10/0x20 kernel/sched/core.c:2148
 [<ffffffff81157cc4>] signal_wake_up_state+0x44/0x70 kernel/signal.c:659
 [<ffffffff8115835b>] signal_wake_up include/linux/sched.h:3332 [inline]
 [<ffffffff8115835b>] complete_signal+0x62b/0x790 kernel/signal.c:942
 [<ffffffff811598a5>] __send_signal+0x4d5/0x11b0 kernel/signal.c:1080
 [<ffffffff8115a5ca>] send_signal+0x4a/0xc0 kernel/signal.c:1096
 [<ffffffff8115ccb4>] do_send_sig_info+0xa4/0x130 kernel/signal.c:1151
 [<ffffffff8115cd73>] send_sig_info+0x33/0x50 kernel/signal.c:1436
 [<ffffffff81328e6d>] zap_pid_ns_processes+0x28d/0x690 kernel/pid_namespace.c:223
 [<ffffffff811386b1>] find_child_reaper kernel/exit.c:477 [inline]
 [<ffffffff811386b1>] forget_original_parent kernel/exit.c:563 [inline]
 [<ffffffff811386b1>] exit_notify kernel/exit.c:599 [inline]
 [<ffffffff811386b1>] do_exit+0x1c21/0x26b0 kernel/exit.c:776
 [<ffffffff8113d3b1>] do_group_exit+0x111/0x330 kernel/exit.c:885
 [<ffffffff8113d5ed>] SYSC_exit_group kernel/exit.c:896 [inline]
 [<ffffffff8113d5ed>] SyS_exit_group+0x1d/0x20 kernel/exit.c:894
 [<ffffffff838c8c65>] 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  [<ffffffff81226f45>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
 RSP <ffff8801d6c578b8>
CR2: fffffffde4ad6880
---[ end trace fd6ed9200f55fbfb ]---