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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 ffff88809afee28b by task syz-executor0/8293

CPU: 1 PID: 8293 Comm: syz-executor0 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:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443
 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:00007f8384014c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457ec9
RDX: 000000000000000e RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f83840156d4
R13: 00000000004c5284 R14: 00000000004d8ba8 R15: 00000000ffffffff

Allocated by task 1:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x700 mm/slab.c:3554
 kmem_cache_zalloc include/linux/slab.h:731 [inline]
 __kernfs_new_node+0xfe/0x8a0 fs/kernfs/dir.c:634
 kernfs_new_node+0x99/0x130 fs/kernfs/dir.c:695
 __kernfs_create_file+0x51/0x340 fs/kernfs/file.c:992
 sysfs_add_file_mode_ns+0x222/0x560 fs/sysfs/file.c:306
 sysfs_merge_group+0x21f/0x400 fs/sysfs/group.c:317
 dpm_sysfs_add+0x164/0x210 drivers/base/power/sysfs.c:656
 device_add+0xa07/0x1800 drivers/base/core.c:1924
 netdev_register_kobject+0x18c/0x390 net/core/net-sysfs.c:1751
 register_netdevice+0x8e1/0x10b0 net/core/dev.c:8629
 register_netdev+0x30/0x50 net/core/dev.c:8744
 nr_proto_init+0x29a/0x591 net/netrom/af_netrom.c:1416
 do_one_initcall+0x129/0x937 init/main.c:889
 do_initcall_level init/main.c:957 [inline]
 do_initcalls init/main.c:965 [inline]
 do_basic_setup init/main.c:983 [inline]
 kernel_init_freeable+0x4db/0x5cf init/main.c:1147
 kernel_init+0x12/0x1c5 init/main.c:1067
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88809afee1c0
 which belongs to the cache kernfs_node_cache of size 160
The buggy address is located 43 bytes to the right of
 160-byte region [ffff88809afee1c0, ffff88809afee260)
The buggy address belongs to the page:
page:ffffea00026bfb80 count:1 mapcount:0 mapping:ffff88812c2be7c0 index:0xffff88809afeefee
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00026bfb08 ffffea00026bfc08 ffff88812c2be7c0
raw: ffff88809afeefee ffff88809afee000 0000000100000012 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809afee180: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88809afee200: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff88809afee280: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffff88809afee300: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88809afee380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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