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BUG: KASAN: slab-out-of-bounds in __xfrm6_tunnel_alloc_spi net/ipv6/xfrm6_tunnel.c:124 [inline]
BUG: KASAN: slab-out-of-bounds in xfrm6_tunnel_alloc_spi+0x779/0x8a0 net/ipv6/xfrm6_tunnel.c:174
Read of size 4 at addr ffff888214c81c00 by task syz-executor719/6813
CPU: 1 PID: 6813 Comm: syz-executor719 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_alloc_spi net/ipv6/xfrm6_tunnel.c:124 [inline]
 xfrm6_tunnel_alloc_spi+0x779/0x8a0 net/ipv6/xfrm6_tunnel.c:174
 ipcomp6_tunnel_create net/ipv6/ipcomp6.c:84 [inline]
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:124 [inline]
 ipcomp6_init_state net/ipv6/ipcomp6.c:159 [inline]
 ipcomp6_init_state+0x2af/0x700 net/ipv6/ipcomp6.c:139
 __xfrm_init_state+0x9a6/0x14b0 net/xfrm/xfrm_state.c:2498
 xfrm_init_state+0x1a/0x70 net/xfrm/xfrm_state.c:2525
 pfkey_msg2xfrm_state net/key/af_key.c:1291 [inline]
 pfkey_add+0x1a10/0x2b70 net/key/af_key.c:1508
 pfkey_process+0x66d/0x7a0 net/key/af_key.c:2834
 pfkey_sendmsg+0x42d/0x800 net/key/af_key.c:3673
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x331/0x810 net/socket.c:2362
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2416
 __sys_sendmmsg+0x195/0x480 net/socket.c:2506
 __do_sys_sendmmsg net/socket.c:2535 [inline]
 __se_sys_sendmmsg net/socket.c:2532 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2532
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440409
Code: Bad RIP value.
RSP: 002b:00007fffb7d79f48 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440409
RDX: 0400000000000282 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401c10
R13: 0000000000401ca0 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 1:
 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
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x1a8/0x320 mm/slab.c:3664
 kmalloc include/linux/slab.h:559 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 arpt_alloc_initial_table+0x66/0x6a0 net/ipv4/netfilter/arp_tables.c:40
 arptable_filter_table_init net/ipv4/netfilter/arptable_filter.c:50 [inline]
 arptable_filter_table_init net/ipv4/netfilter/arptable_filter.c:42 [inline]
 arptable_filter_init+0xcd/0x149 net/ipv4/netfilter/arptable_filter.c:85
 do_one_initcall+0x10a/0x7b0 init/main.c:1201
 do_initcall_level init/main.c:1274 [inline]
 do_initcalls init/main.c:1290 [inline]
 do_basic_setup init/main.c:1310 [inline]
 kernel_init_freeable+0x4f4/0x5a3 init/main.c:1507
 kernel_init+0xd/0x1c0 init/main.c:1401
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
The buggy address belongs to the object at ffff888214c81000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1024 bytes to the right of
 2048-byte region [ffff888214c81000, ffff888214c81800)
The buggy address belongs to the page:
page:00000000eedb9c72 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888214c81000 pfn:0x214c81
flags: 0x57ffe0000000200(slab)
raw: 057ffe0000000200 ffffea00085e0188 ffffea0008534348 ffff8880aa000800
raw: ffff888214c81000 ffff888214c81000 0000000100000000 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff888214c81b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888214c81b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888214c81c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888214c81c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888214c81d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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