------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1087 at mark_buffer_dirty+0x299/0x410, CPU#1: syz.6.22303/21754
Modules linked in:
CPU: 1 UID: 0 PID: 21754 Comm: syz.6.22303 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(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 f9 ec de ff 49 8b 3e be 40 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 34 63 fb ff e8 df 52 75 ff eb 8c e8 d8 52 75 ff 90 <0f> 0b 90 e9 a5 fd ff ff e8 ca 52 75 ff 90 0f 0b 90 e9 cf fd ff ff
RSP: 0018:ffffc9000559e3e8 EFLAGS: 00010293
RAX: ffffffff824f7948 RBX: ffff888179932000 RCX: ffff888112d88000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88811adde001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed102f326401 R12: ffff88817cee5800
R13: ffff8881798a0b90 R14: ffff888179932000 R15: 0000000000000012
FS:  00007f95d581e6c0(0000) GS:ffff8882a9f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f395c197dac CR3: 000000011b096000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 bfs_get_block+0x5e6/0xaf0
 __block_write_begin_int+0x6c6/0x1910
 block_write_begin+0x8d/0x120
 bfs_write_begin+0x35/0xd0
 generic_perform_write+0x2af/0x8b0
 generic_file_write_iter+0x14b/0x690
 __kernel_write_iter+0x427/0x890
 __kernel_write+0x106/0x170
 dump_emit+0x8ec/0xab0
 elf_core_dump+0x2e5d/0x3ad0
 coredump_write+0x1221/0x1920
 vfs_coredump+0x380d/0x4540
 get_signal+0x1107/0x1330
 arch_do_signal_or_restart+0xbc/0x840
 irqentry_exit+0x289/0x760
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f95d75ccde1
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: 00007f95d7845fa0 RCX: 00007f95d75ccdd9
RDX: 0000000000000000 RSI: 00000000fffffeb0 RDI: 0000000002000400
RBP: 00007f95d7662d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f95d7846038 R14: 00007f95d7845fa0 R15: 00007ffede5d4b28
 </TASK>
