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BUG: KASAN: use-after-free in rt6_select net/ipv6/route.c:757 [inline]
BUG: KASAN: use-after-free in ip6_pol_route+0x2989/0x2bb0 net/ipv6/route.c:1093
Read of size 4 at addr ffff8801c2ee6da8 by task syz-executor6/5439

CPU: 1 PID: 5439 Comm: syz-executor6 Not tainted 4.13.0-rc4+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
sctp: [Deprecated]: syz-executor5 (pid 5447) Use of int in max_burst socket option deprecated.
Use struct sctp_assoc_value instead
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x7f/0x260 mm/kasan/report.c:252
sctp: [Deprecated]: syz-executor5 (pid 5444) Use of int in max_burst socket option deprecated.
Use struct sctp_assoc_value instead
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 rt6_select net/ipv6/route.c:757 [inline]
 ip6_pol_route+0x2989/0x2bb0 net/ipv6/route.c:1093
 ip6_pol_route_output+0x4c/0x60 net/ipv6/route.c:1217
 fib6_rule_lookup+0x9e/0x2a0 net/ipv6/ip6_fib.c:281
 ip6_route_output_flags+0x1f1/0x2b0 net/ipv6/route.c:1245
 ip6_route_output include/net/ip6_route.h:80 [inline]
 ip6_dst_lookup_tail+0x4ea/0x970 net/ipv6/ip6_output.c:953
 ip6_dst_lookup_flow+0xc8/0x270 net/ipv6/ip6_output.c:1076
 tcp_v6_connect+0xdd8/0x20e0 net/ipv6/tcp_ipv6.c:255
 __inet_stream_connect+0x2d4/0xf00 net/ipv4/af_inet.c:618
 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:682
 SYSC_connect+0x204/0x470 net/socket.c:1642
 SyS_connect+0x24/0x30 net/socket.c:1623
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512e9
RSP: 002b:00007f9cd3ddbc08 EFLAGS: 00000216 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004512e9
RDX: 000000000000001c RSI: 0000000020000fe4 RDI: 0000000000000005
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000000
R13: 0000000000a6f7ef R14: 00007f9cd3ddc9c0 R15: 0000000000000000

Allocated by task 1137:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xaa/0xd0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x101/0x6e0 mm/slab.c:3561
 dst_alloc+0x11f/0x1a0 net/core/dst.c:107
 __ip6_dst_alloc+0x34/0x60 net/ipv6/route.c:355
 ip6_dst_alloc+0x2d/0x1f0 net/ipv6/route.c:368
 ip6_route_info_create+0x4c6/0x24e0 net/ipv6/route.c:1871
 ip6_route_add+0xa2/0x1a0 net/ipv6/route.c:2108
 ipv6_route_ioctl+0x4cf/0x690 net/ipv6/route.c:2624
 inet6_ioctl+0xef/0x1e0 net/ipv6/af_inet6.c:520
 sock_do_ioctl+0x65/0xb0 net/socket.c:961
 sock_ioctl+0x2c2/0x440 net/socket.c:1058
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 3514:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x6e/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x71/0x240 mm/slab.c:3763
 dst_destroy+0x1de/0x2d0 net/core/dst.c:138
 dst_destroy_rcu+0x16/0x20 net/core/dst.c:151
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2777 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:3031 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2998 [inline]
 rcu_process_callbacks+0xd3e/0x17b0 kernel/rcu/tree.c:3015
 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284

The buggy address belongs to the object at ffff8801c2ee6c40
 which belongs to the cache ip6_dst_cache of size 384
The buggy address is located 360 bytes inside of
 384-byte region [ffff8801c2ee6c40, ffff8801c2ee6dc0)
The buggy address belongs to the page:
page:ffffea00062a4250 count:1 mapcount:0 mapping:ffff8801c2ee6000 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801c2ee6000 0000000000000000 0000000100000009
raw: ffffea0005de4490 ffffea000641b1a8 ffff8801d535cc00
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c2ee6c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c2ee6d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c2ee6d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                  ^
 ffff8801c2ee6e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c2ee6e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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