random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 104 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 109 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 114 bits of entropy available)
==================================================================
BUG: KASAN: use-after-free in ip6_dst_idev include/net/ip6_fib.h:141 [inline]
BUG: KASAN: use-after-free in ip6_xmit+0x1a2c/0x1a70 net/ipv6/ip6_output.c:237
Read of size 8 at addr ffff8800b02d1518 by task syzkaller406418/3770

CPU: 1 PID: 3770 Comm: syzkaller406418 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 497b058e007bcb0a ffff8801c50177e0 ffffffff81d0408d
 ffffea0002c0b440 ffff8800b02d1518 0000000000000000 ffff8800b02d1518
 0000000000000040 ffff8801c5017818 ffffffff814fe143 ffff8800b02d1518
Call Trace:
 [<ffffffff81d0408d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0408d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff814fe143>] print_address_description+0x73/0x260 mm/kasan/report.c:252
 [<ffffffff814fe655>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff814fe655>] kasan_report+0x285/0x370 mm/kasan/report.c:408
 [<ffffffff814fe7b4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff8330649c>] ip6_dst_idev include/net/ip6_fib.h:141 [inline]
 [<ffffffff8330649c>] ip6_xmit+0x1a2c/0x1a70 net/ipv6/ip6_output.c:237
 [<ffffffff833c70f6>] inet6_csk_xmit+0x246/0x480 net/ipv6/inet6_connection_sock.c:176
 [<ffffffff83459bef>] l2tp_xmit_core net/l2tp/l2tp_core.c:1084 [inline]
 [<ffffffff83459bef>] l2tp_xmit_skb+0xc2f/0xea0 net/l2tp/l2tp_core.c:1179
 [<ffffffff834666d4>] pppol2tp_sendmsg+0x584/0x7f0 net/l2tp/l2tp_ppp.c:355
 [<ffffffff82deba6a>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82deba6a>] sock_sendmsg+0xca/0x110 net/socket.c:635
 [<ffffffff82dec9b8>] SYSC_sendto+0x2c8/0x340 net/socket.c:1665
 [<ffffffff82deeeb0>] SyS_sendto+0x40/0x50 net/socket.c:1633
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

Allocated by task 3754:
 [<ffffffff81035d96>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fd1b3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fd47d>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fd47d>] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814fda52>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f912a>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f912a>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f912a>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f912a>] kmem_cache_alloc+0xba/0x290 mm/slub.c:2628
 [<ffffffff82e6964f>] dst_alloc+0x11f/0x1a0 net/core/dst.c:210
 [<ffffffff830c27d8>] rt_dst_alloc+0x78/0x430 net/ipv4/route.c:1467
 [<ffffffff830cbc6e>] __mkroute_output net/ipv4/route.c:2120 [inline]
 [<ffffffff830cbc6e>] __ip_route_output_key_hash+0xa4e/0x2390 net/ipv4/route.c:2332
 [<ffffffff83195fc5>] __ip_route_output_key include/net/route.h:123 [inline]
 [<ffffffff83195fc5>] ip_route_connect include/net/route.h:296 [inline]
 [<ffffffff83195fc5>] __ip4_datagram_connect+0xa15/0x1150 net/ipv4/datagram.c:51
 [<ffffffff833b8109>] __ip6_datagram_connect+0x4d9/0x1950 net/ipv6/datagram.c:59
 [<ffffffff833b95af>] ip6_datagram_connect+0x2f/0x50 net/ipv6/datagram.c:223
 [<ffffffff831d0a1b>] inet_dgram_connect+0x16b/0x1f0 net/ipv4/af_inet.c:550
 [<ffffffff82dec596>] SYSC_connect+0x1b6/0x310 net/socket.c:1557
 [<ffffffff82deee04>] SyS_connect+0x24/0x30 net/socket.c:1538
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

Freed by task 0:
 [<ffffffff81035d96>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fd1b3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fdad2>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fdad2>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814fa217>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814fa217>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814fa217>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814fa217>] kmem_cache_free+0xc7/0x320 mm/slub.c:2881
 [<ffffffff82e6a2ee>] dst_destroy+0x20e/0x330 net/core/dst.c:270
 [<ffffffff82e6a935>] dst_destroy_rcu+0x15/0x40 net/core/dst.c:295
 [<ffffffff812950d4>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff812950d4>] rcu_do_batch kernel/rcu/tree.c:2705 [inline]
 [<ffffffff812950d4>] invoke_rcu_callbacks kernel/rcu/tree.c:2973 [inline]
 [<ffffffff812950d4>] __rcu_process_callbacks kernel/rcu/tree.c:2940 [inline]
 [<ffffffff812950d4>] rcu_process_callbacks+0x7f4/0x14a0 kernel/rcu/tree.c:2957
 [<ffffffff83776e57>] __do_softirq+0x227/0xa38 kernel/softirq.c:273

The buggy address belongs to the object at ffff8800b02d1500
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8800b02d1500, ffff8800b02d15d0)
The buggy address belongs to the page: