==================================================================
BUG: KASAN: use-after-free in ip6_dst_idev include/net/ip6_fib.h:141 [inline]
BUG: KASAN: use-after-free in ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
Read of size 8 at addr ffff8801c918b8d8 by task syz-executor0/19133
input: syz1 as /devices/virtual/input/input278

CPU: 1 PID: 19133 Comm: syz-executor0 Not tainted 4.4.150-g5541782 #83
input: syz1 as /devices/virtual/input/input279
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 4a71e2115b06ea60 ffff8801cb15f5c8 ffffffff81e14e2d
 ffffea00072462c0 ffff8801c918b8d8 0000000000000000 ffff8801c918b8d8
 0000000000001200 ffff8801cb15f600 ffffffff8151a3f0 ffff8801c918b8d8
Call Trace:
 [<ffffffff81e14e2d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e14e2d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8151a3f0>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff8151a70f>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8151a70f>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fdca4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff83434bcc>] ip6_dst_idev include/net/ip6_fib.h:141 [inline]
 [<ffffffff83434bcc>] ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
 [<ffffffff834f4c15>] inet6_csk_xmit+0x245/0x490 net/ipv6/inet6_connection_sock.c:176
 [<ffffffff835a425b>] l2tp_xmit_core net/l2tp/l2tp_core.c:1084 [inline]
 [<ffffffff835a425b>] l2tp_xmit_skb+0xbeb/0xeb0 net/l2tp/l2tp_core.c:1179
 [<ffffffff835b0790>] pppol2tp_sendmsg+0x4e0/0x7d0 net/l2tp/l2tp_ppp.c:355
 [<ffffffff82f25d2c>] sock_sendmsg_nosec net/socket.c:626 [inline]
 [<ffffffff82f25d2c>] sock_sendmsg+0xcc/0x110 net/socket.c:636
 [<ffffffff82f274f1>] ___sys_sendmsg+0x441/0x880 net/socket.c:1963
 [<ffffffff82f29ace>] __sys_sendmmsg+0x12e/0x2e0 net/socket.c:2048
 [<ffffffff82f29cb5>] SYSC_sendmmsg net/socket.c:2078 [inline]
 [<ffffffff82f29cb5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2073
 [<ffffffff838cb0a5>] entry_SYSCALL_64_fastpath+0x22/0x9e

Allocated by task 18109:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fcd53>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fd037>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fd037>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814fd602>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f911e>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f911e>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f911e>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f911e>] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628
 [<ffffffff82fa4295>] dst_alloc+0xb5/0x1a0 net/core/dst.c:210
 [<ffffffff831f1428>] rt_dst_alloc+0x78/0x430 net/ipv4/route.c:1478
 [<ffffffff831fa8ec>] __mkroute_output net/ipv4/route.c:2132 [inline]
 [<ffffffff831fa8ec>] __ip_route_output_key_hash+0x9ac/0x2380 net/ipv4/route.c:2344
 [<ffffffff831fcd99>] __ip_route_output_key include/net/route.h:124 [inline]
 [<ffffffff831fcd99>] ip_route_output_flow+0x29/0xa0 net/ipv4/route.c:2431
 [<ffffffff832c69f3>] ip_route_connect include/net/route.h:304 [inline]
 [<ffffffff832c69f3>] __ip4_datagram_connect+0x663/0xfe0 net/ipv4/datagram.c:51
 [<ffffffff834e6840>] __ip6_datagram_connect+0x1280/0x1960 net/ipv6/datagram.c:105
 [<ffffffff834e6f4f>] ip6_datagram_connect+0x2f/0x50 net/ipv6/datagram.c:223
 [<ffffffff83301b07>] inet_dgram_connect+0x117/0x200 net/ipv4/af_inet.c:550
 [<ffffffff82f266a8>] SYSC_connect+0x1b8/0x300 net/socket.c:1558
 [<ffffffff82f28fe4>] SyS_connect+0x24/0x30 net/socket.c:1539
 [<ffffffff838cb0a5>] entry_SYSCALL_64_fastpath+0x22/0x9e

Freed by task 3907:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fcd53>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fd682>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fd682>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814fa86e>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814fa86e>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814fa86e>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814fa86e>] kmem_cache_free+0xbe/0x340 mm/slub.c:2881
 [<ffffffff82fa3545>] dst_destroy.part.6+0x1f5/0x330 net/core/dst.c:270
 [<ffffffff82fa3bc5>] dst_destroy net/core/dst.c:252 [inline]
 [<ffffffff82fa3bc5>] dst_destroy_rcu+0x15/0x40 net/core/dst.c:295
 [<ffffffff81288ce7>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff81288ce7>] rcu_do_batch kernel/rcu/tree.c:2705 [inline]
 [<ffffffff81288ce7>] invoke_rcu_callbacks kernel/rcu/tree.c:2973 [inline]
 [<ffffffff81288ce7>] __rcu_process_callbacks kernel/rcu/tree.c:2940 [inline]
 [<ffffffff81288ce7>] rcu_process_callbacks+0x927/0x1440 kernel/rcu/tree.c:2957
 [<ffffffff838ce5bc>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273

The buggy address belongs to the object at ffff8801c918b8c0
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801c918b8c0, ffff8801c918b990)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at ffffed043960d057
IP: [<ffffffff8118bead>] ns_of_pid include/linux/pid.h:140 [inline]
IP: [<ffffffff8118bead>] task_active_pid_ns+0x8d/0xd0 kernel/pid.c:546
PGD 21ff6a067 PUD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 19184 Comm: blkid Not tainted 4.4.150-g5541782 #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b7a41800 task.stack: ffff8800b6668000
RIP: 0010:[<ffffffff8118bead>]  [<ffffffff8118bead>] ns_of_pid include/linux/pid.h:140 [inline]
RIP: 0010:[<ffffffff8118bead>]  [<ffffffff8118bead>] task_active_pid_ns+0x8d/0xd0 kernel/pid.c:546
RSP: 0018:ffff8800b666fd00  EFLAGS: 00010a02
RAX: dffffc0000000000 RBX: ffff8801cb094280 RCX: 0000000000000000
RDX: 1ffff1043960d057 RSI: ffffffff8118be62 RDI: ffff8821cb0682b8
RBP: ffff8800b666fd10 R08: ffff8800b666f970 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffea00
R13: ffff8800b7a41ff0 R14: ffff8800b7a41c98 R15: ffff8801d0f3b700
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed043960d057 CR3: 000000000440c000 CR4: 00000000001606f0
Stack:
 ffff8800b7a41800 ffff8800b6670000 ffff8800b666fd60 ffffffff812f0764
 ffffffff81527470 ffff8801d0f3b700 ffff8801d0f3bb28 ffff8800b7a41800
 ffff8800b6670000 ffff8800b7a41ff0 ffff8800b7a41c98 ffff8801d0f3b700
Call Trace:
 [<ffffffff812f0764>] acct_process+0x24/0x4d0 kernel/acct.c:596
 [<ffffffff81138c45>] do_exit+0x1495/0x26b0 kernel/exit.c:745
 [<ffffffff8113e0d1>] do_group_exit+0x111/0x330 kernel/exit.c:885
 [<ffffffff8113e30d>] SYSC_exit_group kernel/exit.c:896 [inline]
 [<ffffffff8113e30d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:894
 [<ffffffff838cb0a5>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: c0 03 38 d0 7c 04 84 d2 75 4c 44 8b 63 04 4c 89 e0 48 c1 e0 05 48 8d 7c 03 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 36 49 c1 e4 05 4a 8b 5c 23 38 e8 1f 86 1c 00 48 
RIP  [<ffffffff8118bead>] ns_of_pid include/linux/pid.h:140 [inline]
RIP  [<ffffffff8118bead>] task_active_pid_ns+0x8d/0xd0 kernel/pid.c:546
 RSP <ffff8800b666fd00>
CR2: ffffed043960d057
---[ end trace 9fcbb2a30abe3af0 ]---