Process accounting resumed
IPv6: ADDRCONF(NETDEV_UP): macsec0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth0_to_batadv: link is not ready
Process accounting resumed
==================================================================
BUG: KASAN: use-after-free in alloc_branch fs/minix/itree_common.c:92 [inline]
BUG: KASAN: use-after-free in get_block+0xfaa/0x10f0 fs/minix/itree_common.c:191
Write of size 2 at addr ffff888080ed0ba4 by task syz-executor824/7637

CPU: 1 PID: 7637 Comm: syz-executor824 Not tainted 4.14.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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
device veth1_vlan entered promiscuous mode
 alloc_branch fs/minix/itree_common.c:92 [inline]
 get_block+0xfaa/0x10f0 fs/minix/itree_common.c:191
IPv6: ADDRCONF(NETDEV_UP): macvlan0: link is not ready
 minix_get_block+0xd6/0x100 fs/minix/inode.c:379
 __block_write_begin_int+0x337/0x1030 fs/buffer.c:2038
IPv6: ADDRCONF(NETDEV_UP): macvlan1: link is not ready
 __block_write_begin fs/buffer.c:2088 [inline]
 block_write_begin+0x58/0x260 fs/buffer.c:2147
 minix_write_begin+0x35/0xc0 fs/minix/inode.c:415
IPv6: ADDRCONF(NETDEV_UP): veth0_macvtap: link is not ready
 generic_perform_write+0x1c9/0x420 mm/filemap.c:3047
IPv6: ADDRCONF(NETDEV_UP): veth1_macvtap: link is not ready
 __generic_file_write_iter+0x227/0x590 mm/filemap.c:3172
device veth0_macvtap entered promiscuous mode
 generic_file_write_iter+0x2fa/0x650 mm/filemap.c:3200
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
IPv6: ADDRCONF(NETDEV_UP): macvtap0: link is not ready
 __kernel_write+0xf5/0x330 fs/read_write.c:501
 do_acct_process+0xb49/0xf60 kernel/acct.c:520
device veth1_macvtap entered promiscuous mode
 slow_acct_process kernel/acct.c:579 [inline]
 acct_process+0x38a/0x422 kernel/acct.c:605
 do_exit+0x1712/0x2b00 kernel/exit.c:848
IPv6: ADDRCONF(NETDEV_UP): macsec0: link is not ready
 do_group_exit+0x100/0x310 kernel/exit.c:955
IPv6: ADDRCONF(NETDEV_UP): veth0_to_batadv: link is not ready
 SYSC_exit_group kernel/exit.c:966 [inline]
 SyS_exit_group+0x19/0x20 kernel/exit.c:964
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
IPv6: ADDRCONF(NETDEV_UP): veth1_to_batadv: link is not ready
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
RIP: 0033:0x4475c8
RSP: 002b:00007fff65aaef38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004475c8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
RBP: 00000000004c9e90 R08: 00000000000000e7 R09: ffffffffffffffd4
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006dca40 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea000203b400 count:0 mapcount:0 mapping:          (null) index:0x1
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 0000000000000001 00000000ffffffff
raw: ffffea000203a7a0 ffffea000203b320 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888080ed0a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888080ed0b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888080ed0b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888080ed0c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888080ed0c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================