loop0: detected capacity change from 0 to 2048
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
EXT4-fs error (device loop0): ext4_mb_generate_buddy:1289: group 0, block bitmap and bg descriptor inconsistent: 25 vs 150994969 free clusters
Zero length message leads to an empty skb
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2809!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5351 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00224-g8d561baae505 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ext4_do_writepages+0x4607/0x4610 fs/ext4/inode.c:2808
Code: c6 00 8c 9e 8b e8 49 1c b3 fe 90 0f 0b e8 f1 d9 4a ff 4c 89 f7 48 c7 c6 e0 8f 9e 8b e8 32 1c b3 fe 90 0f 0b e8 da d9 4a ff 90 <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000fe97160 EFLAGS: 00010293
RAX: ffffffff8274e056 RBX: 0000004210000000 RCX: ffff888033b3a440
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc9000fe97590 R08: ffff8880448f1377 R09: 1ffff1100891e26e
R10: dffffc0000000000 R11: ffffed100891e26f R12: 0000000000000001
R13: ffffc9000fe975e0 R14: 0000004000000000 R15: dffffc0000000000
FS:  00007f2a83dfd6c0(0000) GS:ffff88808d210000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000043a3d000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
 do_writepages+0x32e/0x550 mm/page-writeback.c:2634
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 file_write_and_wait_range+0x23e/0x340 mm/filemap.c:794
 generic_buffers_fsync_noflush+0x6c/0x180 fs/buffer.c:609
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x332/0xb20 fs/ext4/fsync.c:147
 generic_write_sync include/linux/fs.h:3042 [inline]
 ext4_buffered_write_iter+0x2ca/0x3a0 fs/ext4/file.c:305
 ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a82f8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2a83dfd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2a831b5fa0 RCX: 00007f2a82f8ebe9
RDX: 0000000000000050 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f2a83011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a831b6038 R14: 00007f2a831b5fa0 R15: 00007ffcd0928c88
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_do_writepages+0x4607/0x4610 fs/ext4/inode.c:2808
Code: c6 00 8c 9e 8b e8 49 1c b3 fe 90 0f 0b e8 f1 d9 4a ff 4c 89 f7 48 c7 c6 e0 8f 9e 8b e8 32 1c b3 fe 90 0f 0b e8 da d9 4a ff 90 <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000fe97160 EFLAGS: 00010293
RAX: ffffffff8274e056 RBX: 0000004210000000 RCX: ffff888033b3a440
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc9000fe97590 R08: ffff8880448f1377 R09: 1ffff1100891e26e
R10: dffffc0000000000 R11: ffffed100891e26f R12: 0000000000000001
R13: ffffc9000fe975e0 R14: 0000004000000000 R15: dffffc0000000000
FS:  00007f2a83dfd6c0(0000) GS:ffff88808d210000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000043a3d000 CR4: 0000000000352ef0