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BUG: KASAN: global-out-of-bounds in netlink_policy_dump_add_policy+0x3b6/0x440 net/netlink/policy.c:160
Read of size 1 at addr ffffffff89cc70f0 by task syz-executor.3/11721

CPU: 1 PID: 11721 Comm: syz-executor.3 Not tainted 5.11.0-rc5-next-20210128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5/0x2f8 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 netlink_policy_dump_add_policy+0x3b6/0x440 net/netlink/policy.c:160
 ctrl_dumppolicy_start+0x3e1/0x760 net/netlink/genetlink.c:1181
 genl_start+0x3cc/0x670 net/netlink/genetlink.c:604
 __netlink_dump_start+0x584/0x900 net/netlink/af_netlink.c:2363
 genl_family_rcv_msg_dumpit+0x2af/0x310 net/netlink/genetlink.c:686
 genl_family_rcv_msg net/netlink/genetlink.c:780 [inline]
 genl_rcv_msg+0x434/0x580 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:674
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2437
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2d4e85ec68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 00000000200029c0 RDI: 0000000000000004
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffd14648c3f R14: 00007f2d4e85f9c0 R15: 000000000119bf8c

The buggy address belongs to the variable:
 vdpa_nl_policy+0x90/0x3a00

Memory state around the buggy address:
 ffffffff89cc6f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffffff89cc7000: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
>ffffffff89cc7080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9
                                                             ^
 ffffffff89cc7100: f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9 00 00 07 f9
 ffffffff89cc7180: f9 f9 f9 f9 00 00 00 01 f9 f9 f9 f9 00 07 f9 f9
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