IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
batman_adv: batadv0: Interface deactivated: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_0
==================================================================
BUG: KASAN: use-after-free in batadv_iv_ogm_schedule+0xd9b/0xdf0 net/batman-adv/bat_iv_ogm.c:951
Write of size 2 at addr ffff8880937e0c96 by task kworker/u4:0/5

CPU: 0 PID: 5 Comm: kworker/u4:0 Not tainted 4.14.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 batadv_iv_ogm_schedule+0xd9b/0xdf0 net/batman-adv/bat_iv_ogm.c:951
 batadv_iv_send_outstanding_bat_ogm_packet+0x4ad/0x6a0 net/batman-adv/bat_iv_ogm.c:1809
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 8804:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15b/0x7c0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 batadv_tvlv_realloc_packet_buff net/batman-adv/tvlv.c:288 [inline]
 batadv_tvlv_container_ogm_append+0x12a/0x490 net/batman-adv/tvlv.c:329
 batadv_iv_ogm_schedule+0xb78/0xdf0 net/batman-adv/bat_iv_ogm.c:945
 batadv_iv_send_outstanding_bat_ogm_packet+0x4ad/0x6a0 net/batman-adv/bat_iv_ogm.c:1809
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Freed by task 2330:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 batadv_iv_ogm_iface_disable+0x34/0x70 net/batman-adv/bat_iv_ogm.c:393
 batadv_hardif_disable_interface.cold+0x61e/0x867 net/batman-adv/hard-interface.c:836
 batadv_softif_destroy_netlink+0xa3/0x140 net/batman-adv/soft-interface.c:1134
 default_device_exit_batch+0x209/0x380 net/core/dev.c:8734
 ops_exit_list.isra.0+0xef/0x140 net/core/net_namespace.c:145
 cleanup_net+0x3bb/0x820 net/core/net_namespace.c:484
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff8880937e0c80
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 22 bytes inside of
 64-byte region [ffff8880937e0c80, ffff8880937e0cc0)
The buggy address belongs to the page:
page:ffffea00024df800 count:1 mapcount:0 mapping:ffff8880937e0000 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880937e0000 0000000000000000 0000000100000020
raw: ffffea00022b09e0 ffffea0002934e20 ffff88812fe56340 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880937e0b80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880937e0c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880937e0c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                         ^
 ffff8880937e0d00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
 ffff8880937e0d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================