syzbot

loop0: detected capacity change from 0 to 64
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4432 at fs/buffer.c:1081 mark_buffer_dirty+0x383/0x7a0 fs/buffer.c:1081
Modules linked in:
CPU: 1 PID: 4432 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:mark_buffer_dirty+0x383/0x7a0 fs/buffer.c:1081
Code: 93 d2 e2 ff 49 8b 3f be 04 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 bc bc fc ff e8 77 a3 92 ff e9 43 ff ff ff e8 6d a3 92 ff <0f> 0b e9 ba fc ff ff e8 61 a3 92 ff 0f 0b e9 00 fd ff ff e8 55 a3
RSP: 0018:ffffc900035a77e8 EFLAGS: 00010293
RAX: ffffffff81ee32f3 RBX: ffff8880717763a0 RCX: ffff88802cfbd940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff8880694b9701 R08: dffffc0000000000 R09: ffffed100e2eec75
R10: ffffed100e2eec75 R11: 1ffff1100e2eec74 R12: ffff88807ab18160
R13: 0000000000000200 R14: ffff8880699e6600 R15: 000000000000000a
FS:  00007f947f66a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000074316000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bfs_move_block fs/bfs/file.c:43 [inline]
 bfs_move_blocks fs/bfs/file.c:56 [inline]
 bfs_get_block+0x58f/0xa50 fs/bfs/file.c:125
 __block_write_begin_int+0x54b/0x1a70 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x96/0x1e0 fs/buffer.c:2102
 bfs_write_begin+0x31/0xd0 fs/bfs/file.c:177
 generic_perform_write+0x2db/0x560 mm/filemap.c:3846
 __generic_file_write_iter+0x172/0x430 mm/filemap.c:3974
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f947e78efc9
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:00007f947f66a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f947e9e5fa0 RCX: 00007f947e78efc9
RDX: 000000000208e24b RSI: 0000200000000440 RDI: 0000000000000004
RBP: 00007f947e811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f947e9e6038 R14: 00007f947e9e5fa0 R15: 00007fffb84c2898
 </TASK>