------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in drivers/md/md.c:1726:29
index 28 is out of range for type 'mdp_disk_t [27]'
CPU: 3 UID: 0 PID: 14532 Comm: syz.6.2303 Tainted: G             L     Y syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455
 super_90_sync+0x1c95/0x1ff0 drivers/md/md.c:1726
 sync_super drivers/md/md.c:2505 [inline]
 sync_sbs drivers/md/md.c:2747 [inline]
 md_update_sb+0xbba/0x2840 drivers/md/md.c:2923
 new_level_store+0x14f/0x1d0 drivers/md/md.c:4268
 md_attr_store+0x1c5/0x330 drivers/md/md.c:6158
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5fa459f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5fa540e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5fa4825fa0 RCX: 00007f5fa459f559
RDX: 0000000000000001 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007f5fa4636b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5fa4826038 R14: 00007f5fa4825fa0 R15: 00007ffdf08632b8
 </TASK>
---[ end trace ]---