folio expected an open fid inode->i_ino=3ac0159
WARNING: fs/9p/vfs_addr.c:39 at v9fs_begin_writeback fs/9p/vfs_addr.c:39 [inline], CPU#0: kworker/u32:7/1144
WARNING: fs/9p/vfs_addr.c:39 at v9fs_begin_writeback+0x1ed/0x260 fs/9p/vfs_addr.c:33, CPU#0: kworker/u32:7/1144
Modules linked in:
CPU: 0 UID: 0 PID: 1144 Comm: kworker/u32:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: writeback wb_workfn (flush-9p-1)
RIP: 0010:v9fs_begin_writeback fs/9p/vfs_addr.c:39 [inline]
RIP: 0010:v9fs_begin_writeback+0x1f1/0x260 fs/9p/vfs_addr.c:33
Code: 90 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 40 48 89 fa 48 c1 ea 03 80 3c 02 00 75 6b 48 8d 3d 83 6e fb 0c 48 8b 73 40 <67> 48 0f b9 3a eb 89 e8 73 0c 94 fe e9 a3 fe ff ff e8 f9 0c 94 fe
RSP: 0018:ffffc90006627418 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88803bbd8660 RCX: 0000000000000000
RDX: 1ffff1100777b0d4 RSI: 0000000003ac0159 RDI: ffffffff90902260
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffed100777b0dc
R10: ffff88803bbd86e3 R11: ffff8880296baff0 R12: ffff888035f28450
R13: ffffc90006627768 R14: dffffc0000000000 R15: ffff888035f286d8
FS:  0000000000000000(0000) GS:ffff8880d68f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555558b585c8 CR3: 0000000037b3e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 netfs_writepages+0x6e7/0x920 fs/netfs/write_issue.c:591
 do_writepages+0x27a/0x600 mm/page-writeback.c:2598
 __writeback_single_inode+0x168/0x14a0 fs/fs-writeback.c:1737
 writeback_sb_inodes+0x72e/0x1ce0 fs/fs-writeback.c:2030
 wb_writeback+0x419/0xae0 fs/fs-writeback.c:2216
 wb_do_writeback fs/fs-writeback.c:2363 [inline]
 wb_workfn+0x14d/0xbb0 fs/fs-writeback.c:2403
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
   9:	fc ff df
   c:	48 8d 7b 40          	lea    0x40(%rbx),%rdi
  10:	48 89 fa             	mov    %rdi,%rdx
  13:	48 c1 ea 03          	shr    $0x3,%rdx
  17:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  1b:	75 6b                	jne    0x88
  1d:	48 8d 3d 83 6e fb 0c 	lea    0xcfb6e83(%rip),%rdi        # 0xcfb6ea7
  24:	48 8b 73 40          	mov    0x40(%rbx),%rsi
* 28:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2d:	eb 89                	jmp    0xffffffb8
  2f:	e8 73 0c 94 fe       	call   0xfe940ca7
  34:	e9 a3 fe ff ff       	jmp    0xfffffedc
  39:	e8 f9 0c 94 fe       	call   0xfe940d37