syzbot

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BUG: KASAN: slab-out-of-bounds in fib6_rule_suppress+0x25a/0x270 net/ipv6/fib6_rules.c:273
Read of size 8 at addr ffff888084539ae8 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.2.0-rc3+ #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 fib6_rule_suppress+0x25a/0x270 net/ipv6/fib6_rules.c:273
 fib_rules_lookup+0x81d/0xa90 net/core/fib_rules.c:306
 fib6_rule_lookup+0x384/0x5a0 net/ipv6/fib6_rules.c:108
 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2082
 ip6_route_input+0x5e2/0x9e0 net/ipv6/route.c:2217
 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:63
 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:74
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4981
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5095
 process_backlog+0x206/0x750 net/core/dev.c:5906
 napi_poll net/core/dev.c:6329 [inline]
 net_rx_action+0x4f5/0x1070 net/core/dev.c:6395
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 run_ksoftirqd kernel/softirq.c:604 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:596
 smpboot_thread_fn+0x6a3/0xa30 kernel/smpboot.c:165
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 8503:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488
 dst_alloc+0x10e/0x200 net/core/dst.c:93
 ip6_dst_alloc+0x34/0xa0 net/ipv6/route.c:352
 ip6_rt_pcpu_alloc net/ipv6/route.c:1281 [inline]
 rt6_make_pcpu_route net/ipv6/route.c:1310 [inline]
 ip6_pol_route+0x596/0xf40 net/ipv6/route.c:2054
 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:2070
 fib6_rule_lookup+0x133/0x5a0 net/ipv6/fib6_rules.c:116
 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2082
 ip6_route_input+0x5e2/0x9e0 net/ipv6/route.c:2217
 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:63
 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:74
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4981
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5095
 process_backlog+0x206/0x750 net/core/dev.c:5906
 napi_poll net/core/dev.c:6329 [inline]
 net_rx_action+0x4f5/0x1070 net/core/dev.c:6395
 __do_softirq+0x25c/0x94c kernel/softirq.c:293

Freed by task 9:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3698
 dst_destroy+0x29e/0x3c0 net/core/dst.c:129
 dst_destroy_rcu+0x16/0x19 net/core/dst.c:142
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2092 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
 rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291
 __do_softirq+0x25c/0x94c kernel/softirq.c:293

The buggy address belongs to the object at ffff888084539a00
 which belongs to the cache ip6_dst_cache of size 224
The buggy address is located 8 bytes to the right of
 224-byte region [ffff888084539a00, ffff888084539ae0)
The buggy address belongs to the page:
page:ffffea0002114e40 refcount:1 mapcount:0 mapping:ffff888216bbb180 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002386f88 ffffea000263f708 ffff888216bbb180
raw: 0000000000000000 ffff888084539000 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888084539980: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888084539a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888084539a80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                          ^
 ffff888084539b00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff888084539b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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