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BUG: KASAN: use-after-free in rt6_select net/ipv6/route.c:754 [inline]
BUG: KASAN: use-after-free in ip6_pol_route+0x2989/0x2bb0 net/ipv6/route.c:1090
Read of size 4 at addr ffff8801d2372da8 by task syz-executor1/15847

CPU: 0 PID: 15847 Comm: syz-executor1 Not tainted 4.13.0-rc5+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 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:754 [inline]
 ip6_pol_route+0x2989/0x2bb0 net/ipv6/route.c:1090
 ip6_pol_route_output+0x4c/0x60 net/ipv6/route.c:1214
 fib6_rule_lookup+0x9e/0x2a0 net/ipv6/ip6_fib.c:281
 ip6_route_output_flags+0x1f1/0x2b0 net/ipv6/route.c:1242
 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
 sctp_v6_get_dst+0x667/0x19f0 net/sctp/ipv6.c:274
 sctp_transport_route+0xa8/0x430 net/sctp/transport.c:287
 sctp_assoc_add_peer+0x4fe/0x1100 net/sctp/associola.c:656
 sctp_sendmsg+0x152d/0x31f0 net/sctp/socket.c:1873
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x352/0x5a0 net/socket.c:1750
 SyS_sendto+0x40/0x50 net/socket.c:1718
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512e9
RSP: 002b:00007f2423b56c08 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004512e9
RDX: 0000000000000064 RSI: 0000000020aa3000 RDI: 0000000000000005
RBP: 0000000000000086 R08: 0000000020aa4fe4 R09: 000000000000001c
R10: 0000000000000080 R11: 0000000000000216 R12: 00000000004b70fd
R13: 00000000ffffffff R14: 0000000020aa4000 R15: 0000000000001000

Allocated by task 15802:
 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+0xad/0xe0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x127/0x750 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+0x4b2/0x24c0 net/ipv6/route.c:1863
 ip6_route_add+0xa2/0x1a0 net/ipv6/route.c:2100
 ipv6_route_ioctl+0x4cf/0x690 net/ipv6/route.c:2616
 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 15802:
 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+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x77/0x280 mm/slab.c:3763
 dst_destroy+0x1de/0x2d0 net/core/dst.c:138
 dst_release_immediate+0x4f/0x90 net/core/dst.c:203
 ip6_route_info_create+0x787/0x24c0 net/ipv6/route.c:2088
 ip6_route_add+0xa2/0x1a0 net/ipv6/route.c:2100
 ipv6_route_ioctl+0x4cf/0x690 net/ipv6/route.c:2616
 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

The buggy address belongs to the object at ffff8801d2372c40
 which belongs to the cache ip6_dst_cache of size 384
The buggy address is located 360 bytes inside of
 384-byte region [ffff8801d2372c40, ffff8801d2372dc0)
The buggy address belongs to the page:
page:ffffea000748dc80 count:1 mapcount:0 mapping:ffff8801d2372000 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801d2372000 0000000000000000 0000000100000009
raw: ffffea00070ac520 ffff8801d3f96948 ffff8801d3f954c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d2372c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d2372d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d2372d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                  ^
 ffff8801d2372e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d2372e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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