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 ffff8801d6030a18 by task syz-executor0/17654

CPU: 1 PID: 17654 Comm: syz-executor0 Not tainted 4.4.146-g1396226 #79
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 74b7d24f746cc356 ffff88009e7875c8 ffffffff81e1292d
 ffffea0007580c00 ffff8801d6030a18 0000000000000000 ffff8801d6030a18
 0000000000001a00 ffff88009e787600 ffffffff81517f76 ffff8801d6030a18
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
 [<ffffffff814fbd84>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff8343255c>] ip6_dst_idev include/net/ip6_fib.h:141 [inline]
 [<ffffffff8343255c>] ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
 [<ffffffff834f25a5>] inet6_csk_xmit+0x245/0x490 net/ipv6/inet6_connection_sock.c:176
 [<ffffffff835a1beb>] l2tp_xmit_core net/l2tp/l2tp_core.c:1084 [inline]
 [<ffffffff835a1beb>] l2tp_xmit_skb+0xbeb/0xeb0 net/l2tp/l2tp_core.c:1179
 [<ffffffff835ae120>] pppol2tp_sendmsg+0x4e0/0x7d0 net/l2tp/l2tp_ppp.c:355
 [<ffffffff82f2373c>] sock_sendmsg_nosec net/socket.c:626 [inline]
 [<ffffffff82f2373c>] sock_sendmsg+0xcc/0x110 net/socket.c:636
 [<ffffffff82f24f01>] ___sys_sendmsg+0x441/0x880 net/socket.c:1963
 [<ffffffff82f274de>] __sys_sendmmsg+0x12e/0x2e0 net/socket.c:2048
 [<ffffffff82f276c5>] SYSC_sendmmsg net/socket.c:2078 [inline]
 [<ffffffff82f276c5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2073
 [<ffffffff838c8a25>] entry_SYSCALL_64_fastpath+0x22/0x9e

Allocated by task 14596:
 [<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
 [<ffffffff814fb6e2>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f71de>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f71de>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f71de>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f71de>] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628
 [<ffffffff82fa1ca5>] dst_alloc+0xb5/0x1a0 net/core/dst.c:210
 [<ffffffff831eee08>] rt_dst_alloc+0x78/0x430 net/ipv4/route.c:1478
 [<ffffffff831f82cc>] __mkroute_output net/ipv4/route.c:2132 [inline]
 [<ffffffff831f82cc>] __ip_route_output_key_hash+0x9ac/0x2380 net/ipv4/route.c:2344
 [<ffffffff832c4744>] __ip_route_output_key include/net/route.h:124 [inline]
 [<ffffffff832c4744>] ip_route_connect include/net/route.h:297 [inline]
 [<ffffffff832c4744>] __ip4_datagram_connect+0xa24/0xfe0 net/ipv4/datagram.c:51
 [<ffffffff832c4d2f>] ip4_datagram_connect+0x2f/0x50 net/ipv4/datagram.c:92
 [<ffffffff832ff497>] inet_dgram_connect+0x117/0x200 net/ipv4/af_inet.c:550
 [<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 3:
 [<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
 [<ffffffff814f88ee>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f88ee>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f88ee>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f88ee>] kmem_cache_free+0xbe/0x340 mm/slub.c:2881
 [<ffffffff82fa0f55>] dst_destroy.part.6+0x1f5/0x330 net/core/dst.c:270
 [<ffffffff82fa10a5>] dst_destroy+0x15/0x20 net/core/dst.c:252
 [<ffffffff831f1ebc>] dst_free include/net/dst.h:425 [inline]
 [<ffffffff831f1ebc>] dst_rcu_free+0x9c/0xc0 include/net/dst.h:435
 [<ffffffff81287fb7>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff81287fb7>] rcu_do_batch kernel/rcu/tree.c:2705 [inline]
 [<ffffffff81287fb7>] invoke_rcu_callbacks kernel/rcu/tree.c:2973 [inline]
 [<ffffffff81287fb7>] __rcu_process_callbacks kernel/rcu/tree.c:2940 [inline]
 [<ffffffff81287fb7>] rcu_process_callbacks+0x927/0x1440 kernel/rcu/tree.c:2957
 [<ffffffff838cbf3c>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273

The buggy address belongs to the object at ffff8801d6030a00
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801d6030a00, ffff8801d6030ad0)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
BUG: unable to handle kernel paging request at ffffea0007580c00
IP: [<ffffea0007580c00>] 0xffffea0007580c00
PGD 21f7fa067 PUD 21f7f9067 PMD 800000021e2001e3 
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
------------[ cut here ]------------
WARNING: CPU: 0 PID: 123210752 at kernel/sched/core.c:7946 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941()
do not call blocking ops when !TASK_RUNNING; state=ffffea0007580c00 set at [<ffffffff8148f497>] dump_page mm/debug.c:105 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0007580c00 set at [<ffffffff8148f497>] page_mapcount include/linux/mm.h:464 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0007580c00 set at [<ffffffff8148f497>] dump_page_badflags+0x57/0x70 mm/debug.c:85