FAT-fs (loop2): Invalid FSINFO signature: 0x41615252, 0x80417272 (sector = 1)
------------[ cut here ]------------
cur && cur != mmb
WARNING: fs/buffer.c:639 at mmb_mark_buffer_dirty+0x21a/0x230 fs/buffer.c:639, CPU#0: syz.2.19/5813
Modules linked in:
CPU: 0 UID: 0 PID: 5813 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:mmb_mark_buffer_dirty+0x21a/0x230 fs/buffer.c:639
Code: af d7 ff 4d 89 65 00 eb 05 e8 42 c7 66 ff 4c 89 ff 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 0c d6 8a 09 e8 27 c7 66 ff 90 <0f> 0b 90 e9 39 fe ff ff 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc9000404f660 EFLAGS: 00010293
RAX: ffffffff82615d19 RBX: ffff88811c3c0a80 RCX: ffff888113c71e00
RDX: 0000000000000000 RSI: ffff88811bd3b3b8 RDI: ffff88811c3c0a80
RBP: dffffc0000000000 R08: ffffffff0000ffff R09: ffffffffffffffff
R10: 0000fc000f003000 R11: 65006c0069006641 R12: ffff88811c3c0ad0
R13: dffffc0000000000 R14: ffff88811bd3b3b8 R15: 1ffff1102387815a
FS:  00007f0b764146c0(0000) GS:ffff88818c4bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010ebc0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 fat_add_entries+0xc9a/0x2320 fs/fat/dir.c:1410
 vfat_add_entry+0x2dd3/0x3570 fs/fat/namei_vfat.c:675
 vfat_mkdir+0x16c/0x300 fs/fat/namei_vfat.c:866
 vfs_mkdir+0x40c/0x620 fs/namei.c:5420
 filename_mkdirat+0x285/0x510 fs/namei.c:5453
 __do_sys_mkdirat fs/namei.c:5474 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5471
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0b7559e3c7
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007f0b76413e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f0b76413ee0 RCX: 00007f0b7559e3c7
RDX: 00000000000001ff RSI: 00002000000000c0 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000200000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007f0b76413ea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>