------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1180 at mark_buffer_dirty+0x299/0x440 fs/buffer.c:1180, CPU#0: syz.0.0/5321
Modules linked in:
CPU: 0 UID: 0 PID: 5321 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 01 da ff 49 8b 3e be 40 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 e4 60 fb ff e8 0f 30 6e ff eb 8c e8 08 30 6e ff 90 <0f> 0b 90 e9 a5 fd ff ff e8 fa 2f 6e ff 90 0f 0b 90 e9 cf fd ff ff
RSP: 0018:ffffc9000e216328 EFLAGS: 00010293
RAX: ffffffff82577908 RBX: ffff8880479dabc8 RCX: ffff88803f0124c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff8880409d4001 R08: ffff8880479dabcf R09: 1ffff11008f3b579
R10: dffffc0000000000 R11: ffffed1008f3b57a R12: ffff8880556f2600
R13: ffff8880479da2b8 R14: ffff8880479dabc8 R15: 000000000000000a
FS:  0000000000000000(0000) GS:ffff88808ca56000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feee7b84000 CR3: 0000000043366000 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:4314
 generic_file_write_iter+0x14a/0x680 mm/filemap.c:4457
 __kernel_write_iter+0x41e/0x880 fs/read_write.c:621
 __kernel_write+0x106/0x170 fs/read_write.c:641
 __dump_emit fs/coredump.c:1221 [inline]
 dump_emit+0x8e9/0xab0 fs/coredump.c:1259
 writenote+0x1c0/0x2f0 fs/binfmt_elf.c:1435
 write_note_info fs/binfmt_elf.c:1945 [inline]
 elf_core_dump+0x309a/0x3ad0 fs/binfmt_elf.c:2097
 coredump_write+0x1216/0x1910 fs/coredump.c:1050
 do_coredump fs/coredump.c:1127 [inline]
 vfs_coredump+0x36a9/0x4280 fs/coredump.c:1201
 get_signal+0x1107/0x1330 kernel/signal.c:3019
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0x176/0x620 kernel/entry/common.c:219
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7feef3a52777
Code: e8 8e fa ff ff 89 f2 48 8d 3d 0d 41 1b 00 48 8d 35 34 fa 1d 00 31 c0 e8 e7 f8 ff ff 0f 1f 80 00 00 00 00 53 89 fb 48 83 ec 10 <64> 8b 04 25 a4 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8
RSP: 002b:00007feef49ef160 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007feef3b9c799
RDX: 00007feef49ef180 RSI: 00007feef49ef2b0 RDI: 000000000000000b
RBP: 00007feef3c32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007feef3e16038 R14: 00007feef3e15fa0 R15: 00007ffc42380158
 </TASK>