random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 119 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 126 bits of entropy available)
random: nonblocking pool is initialized
==================================================================
BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
Read of size 4 at addr ffff8801cbb8cf00 by task syz-executor371/3794

CPU: 1 PID: 3794 Comm: syz-executor371 Not tainted 4.4.140-ged9bdc8 #68
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 505f7a758302d437 ffff8800aeb27a80 ffffffff81e0e08d
 ffffea00072ee300 ffff8801cbb8cf00 0000000000000000 ffff8801cbb8cf00
 ffffffff82f19f30 ffff8800aeb27ab8 ffffffff81515a56 ffff8801cbb8cf00
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
 [<ffffffff8115f2b0>] get_signal+0x1190/0x14b0 kernel/signal.c:2151
 [<ffffffff8100df8b>] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712
 [<ffffffff8100360a>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:248
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:348
 [<ffffffff838c2935>] int_ret_from_sys_call+0x25/0xa3

Allocated by task 3794:
 [<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
 [<ffffffff838c27a5>] entry_SYSCALL_64_fastpath+0x22/0x9e

Freed by task 3793:
 [<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
 [<ffffffff83492361>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f2f6dd>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff83491015>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832f8adf>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff8341b740>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<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
 [<ffffffff8115f2b0>] get_signal+0x1190/0x14b0 kernel/signal.c:2151
 [<ffffffff8100df8b>] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712
 [<ffffffff8100360a>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:248
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:348
 [<ffffffff838c2935>] int_ret_from_sys_call+0x25/0xa3

The buggy address belongs to the object at ffff8801cbb8cf00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8801cbb8cf00, ffff8801cbb8d100)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at fffffffde267c6c0
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: 0 PID: 490 Comm: kworker/0:1 Not tainted 4.4.140-ged9bdc8 #68
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events vmstat_shepherd
task: ffff8800bacd9800 task.stack: ffff8800bac38000
RIP: 0010:[<ffffffff81224cf5>]  [<ffffffff81224cf5>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
RSP: 0018:ffff8800bac3f8b8  EFLAGS: 00010046
RAX: 1ffffffff089500f RBX: 0000000000018528 RCX: ffffffff84a14ec0
RDX: fffffbffbc4cf8d8 RSI: fffffffde267c6c0 RDI: ffffffff844a8078
RBP: ffff8800bac3f8f8 R08: ffff8800bacda1f0 R09: 0000000000000001
R10: 0000000000000001 R11: ffff8800bacd9800 R12: ffffffff844a7fa0
R13: dffffc0000000000 R14: 000000002de44818 R15: ffffffffcbb8cf00
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffde267c6c0 CR3: 00000001d1892000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81224c00 0000000000000046 0000000000000003 ffff8801d9304860
 ffff8801d9304800 000000002de44818 ffff8801d93048b0 0000000000000000
 ffff8800bac3f940 ffffffff811d9279 0000000000000005 ffff8801db31f4d8
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
 [<ffffffff811c0585>] wake_up_process+0x15/0x20 kernel/sched/core.c:2142
 [<ffffffff8117c01a>] wake_up_worker kernel/workqueue.c:846 [inline]
 [<ffffffff8117c01a>] insert_work+0x17a/0x210 kernel/workqueue.c:1318
 [<ffffffff8117c48c>] __queue_work+0x3dc/0xea0 kernel/workqueue.c:1433
 [<ffffffff8117d21f>] __queue_delayed_work+0x23f/0x390 kernel/workqueue.c:1495
 [<ffffffff8117efe9>] queue_delayed_work_on+0x59/0xb0 kernel/workqueue.c:1533
 [<ffffffff8146f4d6>] vmstat_shepherd+0x166/0x230 mm/vmstat.c:1488
 [<ffffffff81181f8f>] process_one_work+0x7df/0x1600 kernel/workqueue.c:2064
 [<ffffffff81182e89>] worker_thread+0xd9/0xfc0 kernel/workqueue.c:2196
 [<ffffffff81190998>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c2bd5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
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 <ffff8800bac3f8b8>
CR2: fffffffde267c6c0
---[ end trace 4e1c138e2a139534 ]---