random: sshd: uninitialized urandom read (32 bytes read, 75 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 84 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 90 bits of entropy available)
==================================================================
BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
Read of size 4 at addr ffff8801cbaa2500 by task syz-executor238/3814

CPU: 0 PID: 3814 Comm: syz-executor238 Not tainted 4.4.146-g1396226 #79
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 43dda14cb852393c ffff8801c8c6fcc0 ffffffff81e1292d
 ffffea00072ea880 ffff8801cbaa2500 0000000000000000 ffff8801cbaa2500
 ffffffff82f1f7c0 ffff8801c8c6fcf8 ffffffff81517f76 ffff8801cbaa2500
Call Trace:
 [<ffffffff81e1292d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e1292d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81517f76>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81518295>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81518295>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fbd64>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff835a0ff4>] l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830
 [<ffffffff835adb2f>] pppol2tp_release+0x1ff/0x310 net/l2tp/l2tp_ppp.c:509
 [<ffffffff82f1f696>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f7d6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff81525365>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815258a5>] ____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
 [<ffffffff838c8bb5>] int_ret_from_sys_call+0x25/0xa3

Allocated by task 3815:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae33>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb117>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb117>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f7834>] __kmalloc+0x124/0x310 mm/slub.c:3613
 [<ffffffff835a6439>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff835a6439>] kzalloc include/linux/slab.h:620 [inline]
 [<ffffffff835a6439>] l2tp_session_create+0x39/0x1030 net/l2tp/l2tp_core.c:1748
 [<ffffffff835ab140>] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725
 [<ffffffff82f240b8>] SYSC_connect+0x1b8/0x300 net/socket.c:1558
 [<ffffffff82f269f4>] SyS_connect+0x24/0x30 net/socket.c:1539
 [<ffffffff838c8a25>] entry_SYSCALL_64_fastpath+0x22/0x9e

Freed by task 3815:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fae33>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fb762>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb762>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f8c64>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f8c64>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f8c64>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f8c64>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff835a33a0>] l2tp_session_free+0x170/0x200 net/l2tp/l2tp_core.c:1676
 [<ffffffff835a5759>] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline]
 [<ffffffff835a5759>] l2tp_tunnel_closeall+0x2b9/0x350 net/l2tp/l2tp_core.c:1279
 [<ffffffff835a626b>] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300
 [<ffffffff83498271>] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421
 [<ffffffff82f34f8d>] sk_common_release+0x6d/0x300 net/core/sock.c:2680
 [<ffffffff83496f25>] udp_lib_close+0x15/0x20 include/net/udp.h:190
 [<ffffffff832fe88f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff83421520>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424
 [<ffffffff82f1f696>] sock_release+0x96/0x1c0 net/socket.c:587
 [<ffffffff82f1f7d6>] sock_close+0x16/0x20 net/socket.c:1038
 [<ffffffff81525365>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff815258a5>] ____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
 [<ffffffff838c8bb5>] int_ret_from_sys_call+0x25/0xa3

The buggy address belongs to the object at ffff8801cbaa2500
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8801cbaa2500, ffff8801cbaa2700)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at fffffffde1f28e00
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: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.146-g1396226 #79
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9a41800 task.stack: ffff8801d9a50000
RIP: 0010:[<ffffffff81226f45>]  [<ffffffff81226f45>] cpuacct_charge+0x155/0x380 kernel/sched/cpuacct.c:247
RSP: 0018:ffff8801db307a38  EFLAGS: 00010046
RAX: 1ffffffff089521f RBX: 00000000000185a8 RCX: ffffffff84a16600
RDX: fffffbffbc3e51c0 RSI: fffffffde1f28e00 RDI: ffffffff844a90f8
RBP: ffff8801db307a78 R08: ffff8801d9a421a0 R09: 0000000000000001
R10: 0000000000000001 R11: ffff8801d9a41800 R12: ffffffff844a9020
R13: dffffc0000000000 R14: 00000000288815c5 R15: ffffffffcbaa2500
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffde1f28e00 CR3: 00000001cf60e000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81226e50 0000000000000046 0000000000000003 ffff8800bb9f6060
 ffff8800bb9f6000 00000000288815c5 ffff8800bb9f60b0 0000000000000000
 ffff8801db307ac0 ffffffff811db4c9 0000000000000005 ffff8801db21f558
Call Trace:
 <IRQ> 
 [<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
 [<ffffffff811c27d5>] wake_up_process+0x15/0x20 kernel/sched/core.c:2142
 [<ffffffff8117e26a>] wake_up_worker kernel/workqueue.c:846 [inline]
 [<ffffffff8117e26a>] insert_work+0x17a/0x210 kernel/workqueue.c:1318
 [<ffffffff8117e6dc>] __queue_work+0x3dc/0xea0 kernel/workqueue.c:1433
 [<ffffffff8117f208>] delayed_work_timer_fn+0x68/0x90 kernel/workqueue.c:1472
 [<ffffffff81292d4c>] call_timer_fn+0x18c/0x870 kernel/time/timer.c:1185
 [<ffffffff8129394d>] __run_timers kernel/time/timer.c:1257 [inline]
 [<ffffffff8129394d>] run_timer_softirq+0x51d/0xb90 kernel/time/timer.c:1444
 [<ffffffff838cbf3c>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273
 [<ffffffff81141a8d>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff81141a8d>] irq_exit+0x10d/0x140 kernel/softirq.c:391
 [<ffffffff838cb6a1>] exiting_irq arch/x86/include/asm/apic.h:652 [inline]
 [<ffffffff838cb6a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff838ca5e0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff81025cd5>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81025cd5>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:432
 [<ffffffff81027be0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423
 [<ffffffff8121de97>] default_idle_call+0x57/0x70 kernel/sched/idle.c:93
 [<ffffffff8121e63f>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121e63f>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121e63f>] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301
 [<ffffffff810abf89>] start_secondary+0x329/0x400 arch/x86/kernel/smpboot.c:245
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 <ffff8801db307a38>
CR2: fffffffde1f28e00
---[ end trace 66b0e30b28c5a09f ]---