syzbot

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BUG: KASAN: use-after-free in rawv6_send_hdrinc net/ipv6/raw.c:683 [inline]
BUG: KASAN: use-after-free in rawv6_sendmsg+0x2691/0x2820 net/ipv6/raw.c:916
Read of size 8 at addr ffff8801cdee9d58 by task syz-executor0/6098

CPU: 0 PID: 6098 Comm: syz-executor0 Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801cbb87580 ffffffff81eb95e9 ffffea000737ba00 ffff8801cdee9d58
 0000000000000000 ffff8801cdee9d58 ffff8801cdee9d58 ffff8801cbb875b8
 ffffffff8156c35e ffff8801cdee9d58 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8156c35e>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff8156c768>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff8156c768>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff8153faf4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff835da8c1>] rawv6_send_hdrinc net/ipv6/raw.c:683 [inline]
 [<ffffffff835da8c1>] rawv6_sendmsg+0x2691/0x2820 net/ipv6/raw.c:916
 [<ffffffff83431af3>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770
 [<ffffffff8301e0ac>] sock_sendmsg_nosec net/socket.c:648 [inline]
 [<ffffffff8301e0ac>] sock_sendmsg+0xcc/0x110 net/socket.c:658
 [<ffffffff8301f8ca>] ___sys_sendmsg+0x47a/0x840 net/socket.c:1982
 [<ffffffff83021e31>] __sys_sendmmsg+0x161/0x3d0 net/socket.c:2072
 [<ffffffff830220d5>] SYSC_sendmmsg net/socket.c:2103 [inline]
 [<ffffffff830220d5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2098
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff83a019d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Allocated by task 6098:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547
 slab_post_alloc_hook mm/slab.h:417 [inline]
 slab_alloc_node mm/slub.c:2715 [inline]
 slab_alloc mm/slub.c:2723 [inline]
 kmem_cache_alloc+0xbe/0x290 mm/slub.c:2728
 dst_alloc+0xb5/0x1a0 net/core/dst.c:210
 __ip6_dst_alloc+0x31/0x130 net/ipv6/route.c:334
 ip6_rt_cache_alloc.isra.49+0xe0/0x440 net/ipv6/route.c:956
 ip6_pol_route+0x126d/0x1d30 net/ipv6/route.c:1109
 ip6_pol_route_output+0x4c/0x60 net/ipv6/route.c:1193
 fib6_rule_action+0x23f/0x6b0 net/ipv6/fib6_rules.c:89
 fib_rules_lookup+0x2aa/0x8b0 net/core/fib_rules.c:265
 fib6_rule_lookup+0xe8/0x1a0 net/ipv6/fib6_rules.c:43
 ip6_route_output_flags+0x24b/0x2b0 net/ipv6/route.c:1221
 ip6_dst_lookup_tail+0x3df/0x16c0 net/ipv6/ip6_output.c:991
 ip6_dst_lookup_flow+0xaa/0x210 net/ipv6/ip6_output.c:1092
 rawv6_sendmsg+0x9b5/0x2820 net/ipv6/raw.c:900
 inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770
 sock_sendmsg_nosec net/socket.c:648 [inline]
 sock_sendmsg+0xcc/0x110 net/socket.c:658
 ___sys_sendmsg+0x47a/0x840 net/socket.c:1982
 __sys_sendmmsg+0x161/0x3d0 net/socket.c:2072
 SYSC_sendmmsg net/socket.c:2103 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2098
 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Freed by task 3:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582
 slab_free_hook mm/slub.c:1355 [inline]
 slab_free_freelist_hook mm/slub.c:1377 [inline]
 slab_free mm/slub.c:2958 [inline]
 kmem_cache_free+0xbe/0x310 mm/slub.c:2980
 dst_destroy+0x200/0x360 net/core/dst.c:270
 dst_destroy_rcu+0x15/0x40 net/core/dst.c:295
 __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 __do_softirq+0x210/0x940 kernel/softirq.c:288

The buggy address belongs to the object at ffff8801cdee9c00
 which belongs to the cache ip6_dst_cache of size 384
The buggy address is located 344 bytes inside of
 384-byte region [ffff8801cdee9c00, ffff8801cdee9d80)
The buggy address belongs to the page:
page:ffffea000737ba00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x8000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cdee9c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cdee9c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801cdee9d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8801cdee9d80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801cdee9e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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