------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1180 at mark_buffer_dirty+0x299/0x440 fs/buffer.c:1180, CPU#0: syz.0.0/5331
Modules linked in:
CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:mark_buffer_dirty+0x299/0x440 fs/buffer.c:1180
Code: 4c 89 f7 e8 79 fd d9 ff 49 8b 3e be 40 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 e4 60 fb ff e8 6f 32 6e ff eb 8c e8 68 32 6e ff 90 <0f> 0b 90 e9 a5 fd ff ff e8 5a 32 6e ff 90 0f 0b 90 e9 cf fd ff ff
RSP: 0018:ffffc9000e1a7608 EFLAGS: 00010293
RAX: ffffffff82577e18 RBX: ffff88801f40a910 RCX: ffff888012a2c980
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff888043c3c001 R08: ffff88801f40a917 R09: 1ffff11003e81522
R10: dffffc0000000000 R11: ffffed1003e81523 R12: ffff88801fccd000
R13: ffff88801a87c9f8 R14: ffff88801f40a910 R15: 0000000000000010
FS:  00007f003c5de6c0(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000012ae0000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 bfs_move_block fs/bfs/file.c:44 [inline]
 bfs_move_blocks fs/bfs/file.c:57 [inline]
 bfs_get_block+0x5da/0xae0 fs/bfs/file.c:126
 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2142
 block_write_begin+0x8d/0x120 fs/buffer.c:2253
 bfs_write_begin+0x35/0xd0 fs/bfs/file.c:180
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4319
 generic_file_write_iter+0x14a/0x680 mm/filemap.c:4462
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f003b79c799
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:00007f003c5ddfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f003ba16090 RCX: 00007f003b79c799
RDX: 000000000000fecc RSI: 0000200000000100 RDI: 0000000000000005
RBP: 00007f003b832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f003ba16128 R14: 00007f003ba16090 R15: 00007ffe9fc5ed58
 </TASK>