audit: type=1326 audit(2000000058.700:158): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=_ pid=16373 comm="syz-executor2" exe="/root/syz-executor2" sig=9 arch=c000003e syscall=228 compat=0 ip=0x45ad2a code=0x0
==================================================================
BUG: KASAN: slab-out-of-bounds in batadv_interface_tx+0x1194/0x1880 net/batman-adv/soft-interface.c:226
Read of size 2 at addr ffff888087e3078b by task syz-executor5/16369

CPU: 0 PID: 16369 Comm: syz-executor5 Not tainted 4.20.0+ #2
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145
 batadv_interface_tx+0x1194/0x1880 net/batman-adv/soft-interface.c:226
 __netdev_start_xmit include/linux/netdevice.h:4382 [inline]
 netdev_start_xmit include/linux/netdevice.h:4391 [inline]
 dev_direct_xmit+0x368/0x670 net/core/dev.c:3930
 packet_direct_xmit+0xfb/0x170 net/packet/af_packet.c:246
 packet_snd net/packet/af_packet.c:2932 [inline]
 packet_sendmsg+0x2753/0x6830 net/packet/af_packet.c:2957
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 __sys_sendto+0x387/0x5f0 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ec9
Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f92c61c2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457ec9
RDX: 0000000000000018 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f92c61c36d4
R13: 00000000004c5284 R14: 00000000004d8ba8 R15: 00000000ffffffff

Allocated by task 7811:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 kasan_kmalloc mm/kasan/common.c:482 [inline]
 kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:397
 kmem_cache_alloc+0x12d/0x710 mm/slab.c:3541
 kmem_cache_zalloc include/linux/slab.h:730 [inline]
 __proc_create+0x2f1/0xad0 fs/proc/generic.c:408
 proc_create_reg+0xba/0x180 fs/proc/generic.c:526
 proc_create_single_data+0x91/0x140 fs/proc/generic.c:619
 snmp6_register_dev+0xc3/0x150 net/ipv6/proc.c:258
 ipv6_add_dev net/ipv6/addrconf.c:409 [inline]
 ipv6_add_dev+0x643/0x12c0 net/ipv6/addrconf.c:366
 addrconf_notify+0xa12/0x25f0 net/ipv6/addrconf.c:3452
 notifier_call_chain+0x179/0x380 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739
 call_netdevice_notifiers_extack net/core/dev.c:1751 [inline]
 call_netdevice_notifiers net/core/dev.c:1765 [inline]
 register_netdevice+0xae0/0x10b0 net/core/dev.c:8658
 veth_newlink+0x58d/0xa60 drivers/net/veth.c:1298
 __rtnl_newlink+0x1281/0x1a70 net/core/rtnetlink.c:3182
 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3240
 rtnetlink_rcv_msg+0x481/0xc30 net/core/rtnetlink.c:5125
 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5143
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 __sys_sendto+0x387/0x5f0 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff888087e30680
 which belongs to the cache proc_dir_entry of size 256
The buggy address is located 11 bytes to the right of
 256-byte region [ffff888087e30680, ffff888087e30780)
The buggy address belongs to the page:
page:ffffea00021f8c00 count:1 mapcount:0 mapping:ffff88821bc48800 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00025be588 ffffea000162e488 ffff88821bc48800
raw: 0000000000000000 ffff888087e30040 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888087e30680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888087e30700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888087e30780: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
                      ^
 ffff888087e30800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888087e30880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
==================================================================