IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: 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 ffff8801cba02500 by task syz-executor5/7161

CPU: 0 PID: 7161 Comm: syz-executor5 Not tainted 4.4.138-g226f96b #61
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 bac9283a8345d191 ffff8800b407f868 ffffffff81e0ed0d
 ffffea00072e8080 ffff8801cba02500 0000000000000000 ffff8801cba02500
 ffffffff82f1a2b0 ffff8800b407f8a0 ffffffff81515a16 ffff8801cba02500
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
 [<ffffffff8359ad34>] l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
 [<ffffffff835a786f>] pppol2tp_release+0x1ff/0x310 net/l2tp/l2tp_ppp.c:509
 [<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
 [<ffffffff81135285>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff81135285>] do_exit+0x9e5/0x26b0 kernel/exit.c:759
 [<ffffffff8113b1d1>] do_group_exit+0x111/0x330 kernel/exit.c:889
 [<ffffffff8115e5cc>] get_signal+0x4ec/0x14b0 kernel/signal.c:2321
 [<ffffffff8100df8b>] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712
 [<ffffffff8100360a>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:248
 [<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 7143:
 [<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 7119:
 [<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
 [<ffffffff83492431>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f2fa5d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff834910e5>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832f8bef>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff8341b810>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<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
 [<ffffffff81135285>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff81135285>] do_exit+0x9e5/0x26b0 kernel/exit.c:759
 [<ffffffff8113b1d1>] do_group_exit+0x111/0x330 kernel/exit.c:889
 [<ffffffff8113b40d>] SYSC_exit_group kernel/exit.c:900 [inline]
 [<ffffffff8113b40d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:898
 [<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

The buggy address belongs to the object at ffff8801cba02500
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8801cba02500, ffff8801cba02700)
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: 1 PID: 3880 Comm: syz-executor1 Not tainted 4.4.138-g226f96b #61
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c6779800 task.stack: ffff8801c6608000
RIP: 0010:[<ffffffff81e2c678>]  [<ffffffff81e2c678>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
RSP: 0018:ffff8801db307d30  EFLAGS: 00010803
RAX: ffffed003b66338b RBX: ffff8801db319c40 RCX: ffffffff81e2c7fa
RDX: 1194002a0000037c RSI: ffffffff81e2c65c RDI: 8ca0015000001be7
RBP: ffff8801db307d70 R08: 0000000000000096 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8801c6779800 R12: dffffc0000000000
R13: 8ca0015000001bcf R14: 0000000ac254a480 R15: ffff8801cba02708
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:000000000a2c7900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000835002d CR3: 00000001d16bd000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801db319c58 ffff8801db319710 ffffed003b66338b ffff8801db319700
 ffff8801db319c40 ffff8801db319640 0000000000000001 0000000000000000
 ffff8801db307da8 ffffffff8129b35f ffff8801db319c40 0000000000000001
Call Trace:
 <IRQ> 
 [<ffffffff8129b35f>] enqueue_hrtimer+0x15f/0x440 kernel/time/hrtimer.c:893
 [<ffffffff8129e052>] __run_hrtimer kernel/time/hrtimer.c:1276 [inline]
 [<ffffffff8129e052>] __hrtimer_run_queues+0x6b2/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff8129f4c1>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810ad284>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838c534c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838c4290>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff812d4359>] smp_call_function_many+0x5b9/0x710 kernel/smp.c:435
 [<ffffffff810e8fad>] native_flush_tlb_others+0xfd/0x6e0 arch/x86/mm/tlb.c:292
 [<ffffffff810e969c>] flush_tlb_others arch/x86/include/asm/paravirt.h:338 [inline]
 [<ffffffff810e969c>] flush_tlb_mm_range+0x10c/0x540 arch/x86/mm/tlb.c:358
 [<ffffffff8112bdb9>] dup_mmap kernel/fork.c:528 [inline]
 [<ffffffff8112bdb9>] dup_mm kernel/fork.c:983 [inline]
 [<ffffffff8112bdb9>] copy_mm kernel/fork.c:1037 [inline]
 [<ffffffff8112bdb9>] copy_process+0x4709/0x63e0 kernel/fork.c:1503
 [<ffffffff8112dea6>] _do_fork+0x146/0xe10 kernel/fork.c:1784
 [<ffffffff8112ec47>] SYSC_clone kernel/fork.c:1893 [inline]
 [<ffffffff8112ec47>] SyS_clone+0x37/0x50 kernel/fork.c:1887
 [<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 4d 8b 2f 4d 85 ed 74 3d e8 54 4e 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 22 4e 52 
RIP  [<ffffffff81e2c678>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
 RSP <ffff8801db307d30>
---[ end trace 7d4543e6a8694533 ]---