==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092
Read of size 8 at addr ffff8800acf822a0 by task syz-executor7/12260

CPU: 1 PID: 12260 Comm: syz-executor7 Not tainted 4.4.141-g1b37d68 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 bb7cd25a1b41683e ffff8800b56f7a30 ffffffff81e0e18d
 ffffea0002b3e000 ffff8800acf822a0 0000000000000000 ffff8800acf822a0
 0000000000000000 ffff8800b56f7a68 ffffffff81515a86 ffff8800acf822a0
Call Trace:
 [<ffffffff81e0e18d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e18d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81515a86>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81515da5>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81515da5>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f9894>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff81232cd6>] __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092
 [<ffffffff81235abe>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff838c1e8a>] __raw_spin_lock_bh include/linux/spinlock_api_smp.h:137 [inline]
 [<ffffffff838c1e8a>] _raw_spin_lock_bh+0x3a/0x50 kernel/locking/spinlock.c:175
 [<ffffffff82f26a63>] spin_lock_bh include/linux/spinlock.h:307 [inline]
 [<ffffffff82f26a63>] lock_sock_nested+0x43/0x120 net/core/sock.c:2451
 [<ffffffff835a7bb0>] lock_sock include/net/sock.h:1493 [inline]
 [<ffffffff835a7bb0>] pppol2tp_release+0x50/0x310 net/l2tp/l2tp_ppp.c:493
 [<ffffffff82f1a256>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f1a396>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e75>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815233b5>] ____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:253
 [<ffffffff81007090>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff81007090>] syscall_return_slowpath arch/x86/entry/common.c:349 [inline]
 [<ffffffff81007090>] do_syscall_32_irqs_on arch/x86/entry/common.c:399 [inline]
 [<ffffffff81007090>] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c456a>] sysenter_flags_fixed+0xd/0x17

Allocated by task 12287:
 [<ffffffff81033c86>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f8943>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f8c27>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f8c27>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f5344>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff82f25924>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff82f25924>] sk_prot_alloc+0x204/0x300 net/core/sock.c:1354
 [<ffffffff82f2b2fa>] sk_alloc+0x3a/0x3a0 net/core/sock.c:1419
 [<ffffffff835a3ad3>] pppol2tp_create+0x33/0x1f0 net/l2tp/l2tp_ppp.c:551
 [<ffffffff828f1af6>] pppox_create+0xf6/0x200 drivers/net/ppp/pppox.c:121
 [<ffffffff82f20780>] __sock_create+0x2f0/0x5f0 net/socket.c:1177
 [<ffffffff82f20cb0>] sock_create net/socket.c:1217 [inline]
 [<ffffffff82f20cb0>] SYSC_socket net/socket.c:1247 [inline]
 [<ffffffff82f20cb0>] SyS_socket+0xf0/0x1b0 net/socket.c:1227
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c456a>] sysenter_flags_fixed+0xd/0x17

Freed by task 12260:
 [<ffffffff81033c86>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f8943>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f9272>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f9272>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f6774>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f6774>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f6774>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f6774>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff82f2f7a7>] sk_prot_free net/core/sock.c:1391 [inline]
 [<ffffffff82f2f7a7>] sk_destruct+0x407/0x4c0 net/core/sock.c:1472
 [<ffffffff82f2f8af>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f2fab0>] sk_free+0x30/0x40 net/core/sock.c:1491
 [<ffffffff835a708f>] sock_put include/net/sock.h:1639 [inline]
 [<ffffffff835a708f>] pppol2tp_session_sock_put+0x5f/0x70 net/l2tp/l2tp_ppp.c:286
 [<ffffffff8359f90c>] l2tp_tunnel_closeall+0x23c/0x350 net/l2tp/l2tp_core.c:1277
 [<ffffffff835a049b>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff834927c1>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f2fb2d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff83491475>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832f8f2f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff8341bba0>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<ffffffff82f1a256>] sock_release+0x96/0x1c0 net/socket.c:586
 [<ffffffff82f1a396>] sock_close+0x16/0x20 net/socket.c:1037
 [<ffffffff81522e75>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815233b5>] ____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:253
 [<ffffffff81007090>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff81007090>] syscall_return_slowpath arch/x86/entry/common.c:349 [inline]
 [<ffffffff81007090>] do_syscall_32_irqs_on arch/x86/entry/common.c:399 [inline]
 [<ffffffff81007090>] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c456a>] sysenter_flags_fixed+0xd/0x17

The buggy address belongs to the object at ffff8800acf82200
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 160 bytes inside of
 2048-byte region [ffff8800acf82200, ffff8800acf82a00)
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 4.4.141-g1b37d68 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84417840 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff81e6fc41>]  [<ffffffff81e6fc41>] lookup_object lib/debugobjects.c:120 [inline]
RIP: 0010:[<ffffffff81e6fc41>]  [<ffffffff81e6fc41>] debug_object_deactivate+0x191/0x340 lib/debugobjects.c:465
RSP: 0018:ffff8801db207cf0  EFLAGS: 00010003
RAX: dffffc0000000000 RBX: 4f5f4755425f4d56 RCX: 09ebe8eaa84be9ad
RDX: 0000000000000000 RSI: ffffffff844c6720 RDI: 4f5f4755425f4d6e
RBP: ffff8801db207da8 R08: ffffffff85353140 R09: 0000000000000001
R10: 0000000000000001 R11: ffffffff84417840 R12: 1ffff1003b640fa0
R13: ffffffff859dffa8 R14: ffff8801da0efd28 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc2b426a000 CR3: 00000001d86b7000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000092 ffffffff844c6720 0000000041b58ab3 ffffffff8420a12f
 ffffffff81e6fab0 ffffffff84417840 fffffbfff0883023 ffffffff84418120
 ffff8801db219658 0000000000000000 ffff8801db207d80 ffffffff812296c2
Call Trace:
 <IRQ> 
 [<ffffffff8129dc32>] debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 [<ffffffff8129dc32>] debug_deactivate kernel/time/hrtimer.c:462 [inline]
 [<ffffffff8129dc32>] __run_hrtimer kernel/time/hrtimer.c:1230 [inline]
 [<ffffffff8129dc32>] __hrtimer_run_queues+0x222/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff8129f531>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810ad674>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838c584c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838c4790>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff81025cb5>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81025cb5>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290
 [<ffffffff81027200>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:281
 [<ffffffff8121bc47>] default_idle_call+0x57/0x70 kernel/sched/idle.c:93
 [<ffffffff8121c3ef>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121c3ef>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121c3ef>] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301
 [<ffffffff838afd41>] rest_init+0x188/0x18e init/main.c:410
 [<ffffffff84a4b8a1>] start_kernel+0x6b3/0x6e7 init/main.c:682
 [<ffffffff84a4a30f>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84a4a450>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185
Code: a9 01 00 00 48 8b 1b 41 bf 01 00 00 00 48 85 db 74 42 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18 41 83 c7 01 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 0c 01 00 00 4c 3b 73 18 74 7d 48 89 d9 48 c1 
RIP  [<ffffffff81e6fc41>] lookup_object lib/debugobjects.c:120 [inline]
RIP  [<ffffffff81e6fc41>] debug_object_deactivate+0x191/0x340 lib/debugobjects.c:465
 RSP <ffff8801db207cf0>
---[ end trace eab6d2c86b6176b4 ]---