------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1087 at mark_buffer_dirty+0x299/0x410, CPU#1: syz.0.13149/5384
Modules linked in:
CPU: 1 UID: 0 PID: 5384 Comm: syz.0.13149 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:mark_buffer_dirty+0x299/0x410
Code: 4c 89 f7 e8 89 16 da ff 49 8b 3e be 40 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 94 63 fb ff e8 bf ba 6e ff eb 8c e8 b8 ba 6e ff 90 <0f> 0b 90 e9 a5 fd ff ff e8 aa ba 6e ff 90 0f 0b 90 e9 cf fd ff ff
RSP: 0018:ffffc900064563e8 EFLAGS: 00010293
RAX: ffffffff8256e988 RBX: ffff8881a403dbc8 RCX: ffff8881202f1d80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff8881108b6001 R08: ffff8881a403dbcf R09: 1ffff11034807b79
R10: dffffc0000000000 R11: ffffed1034807b7a R12: ffff8881a7a7d800
R13: ffff88801c41c828 R14: ffff8881a403dbc8 R15: 0000000000000012
FS:  00007f9b4cdf66c0(0000) GS:ffff8882a9290000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f13c8e02440 CR3: 0000000110b5e000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 bfs_get_block+0x5da/0xae0
 __block_write_begin_int+0x6c6/0x1910
 block_write_begin+0x8d/0x120
 bfs_write_begin+0x35/0xd0
 generic_perform_write+0x2e2/0x8f0
 generic_file_write_iter+0x14a/0x680
 __kernel_write_iter+0x41e/0x880
 __kernel_write+0x106/0x170
 dump_emit+0x8e9/0xab0
 elf_core_dump+0x2e5d/0x3ad0
 coredump_write+0x1216/0x1910
 vfs_coredump+0x3807/0x4530
 get_signal+0x1107/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 irqentry_exit+0x284/0x730
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f9b4eb9cde1
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00000000fffffeb0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f9b4ee16180 RCX: 00007f9b4eb9cdd9
RDX: 0000000000000000 RSI: 00000000fffffeb0 RDI: 0000000002000400
RBP: 00007f9b4ec32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f9b4ee16218 R14: 00007f9b4ee16180 R15: 00007fffc4f4c668
 </TASK>
