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BUG: KASAN: slab-out-of-bounds in __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
Read of size 8 at addr ffff88808be87a28 by task syz-executor.2/15247
CPU: 0 PID: 15247 Comm: syz-executor.2 Not tainted 5.8.0-rc5-next-20200716-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
 xfrm6_tunnel_spi_lookup+0x8a/0x1d0 net/ipv6/xfrm6_tunnel.c:95
 xfrmi6_rcv_tunnel+0xb9/0x100 net/xfrm/xfrm_interface.c:824
 tunnel46_rcv+0xef/0x2b0 net/ipv6/tunnel6.c:193
 ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433
 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483
 dst_input include/net/dst.h:449 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401
 netif_receive_skb_internal net/core/dev.c:5503 [inline]
 netif_receive_skb+0x159/0x990 net/core/dev.c:5562
 tun_rx_batched.isra.0+0x460/0x720 drivers/net/tun.c:1518
 tun_get_user+0x23b2/0x35b0 drivers/net/tun.c:1972
 tun_chr_write_iter+0xba/0x151 drivers/net/tun.c:2001
 call_write_iter include/linux/fs.h:1879 [inline]
 new_sync_write+0x422/0x650 fs/read_write.c:515
 vfs_write+0x5c6/0x6f0 fs/read_write.c:595
 ksys_write+0x12d/0x250 fs/read_write.c:648
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x415c91
Code: Bad RIP value.
RSP: 002b:00007f3cb807ec60 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000078bf00 RCX: 0000000000415c91
RDX: 000000000000004a RSI: 0000000020000280 RDI: 00000000000000f0
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000078bf0c
R13: 00007ffdb6a8967f R14: 00007f3cb807f9c0 R15: 000000000078bf0c
Allocated by task 15260:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 kmem_cache_alloc_trace+0x16e/0x2c0 mm/slab.c:3550
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 ep_alloc.constprop.0+0xff/0x370 fs/eventpoll.c:1016
 do_epoll_create+0x97/0x1c0 fs/eventpoll.c:2064
 __do_sys_epoll_create1 fs/eventpoll.c:2095 [inline]
 __se_sys_epoll_create1 fs/eventpoll.c:2093 [inline]
 __x64_sys_epoll_create1+0x2d/0x40 fs/eventpoll.c:2093
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff88808be87800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 40 bytes to the right of
 512-byte region [ffff88808be87800, ffff88808be87a00)
The buggy address belongs to the page:
page:00000000a8f0f40e refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88808be87c00 pfn:0x8be87
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00024fe348 ffffea0002859008 ffff8880aa000600
raw: ffff88808be87c00 ffff88808be87000 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff88808be87900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808be87980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808be87a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff88808be87a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808be87b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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