EXT4-fs error (device loop4): ext4_map_blocks:776: inode #15: comm syz.4.901: lblock 0 mapped to illegal pblock 0 (length 1)
------------[ cut here ]------------
warn && !folio_test_uptodate(folio)
WARNING: mm/page-writeback.c:2666 at __folio_mark_dirty+0x1fb/0xe30 mm/page-writeback.c:2666, CPU#1: syz.4.901/12365
Modules linked in:
CPU: 1 UID: 0 PID: 12365 Comm: syz.4.901 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__folio_mark_dirty+0x1fb/0xe30 mm/page-writeback.c:2666
Code: 3c 38 00 74 08 48 89 df e8 32 1c 28 00 4c 8b 33 4c 89 f6 48 83 e6 08 31 ff e8 c1 03 c2 ff 49 83 e6 08 75 1c e8 56 fe c1 ff 90 <0f> 0b 90 eb 16 e8 4b fe c1 ff e9 60 07 00 00 e8 41 fe c1 ff eb 05
RSP: 0018:ffffc90007587478 EFLAGS: 00010293
RAX: ffffffff820281ea RBX: ffffea0000436800 RCX: ffff88805ed41e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff94000086d01 R12: ffff88803e297070
R13: ffff88803e297068 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fd4de7b66c0(0000) GS:ffff888126438000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000180 CR3: 000000003eeba000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 block_dirty_folio+0x17a/0x1d0 fs/buffer.c:751
 fault_dirty_shared_page+0x103/0x540 mm/memory.c:3619
 wp_page_shared mm/memory.c:4006 [inline]
 do_wp_page+0x20b5/0x49d0 mm/memory.c:4209
 handle_pte_fault mm/memory.c:6333 [inline]
 __handle_mm_fault mm/memory.c:6455 [inline]
 handle_mm_fault+0x9f5/0x13c0 mm/memory.c:6624
 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_4+0xd/0x20 arch/x86/lib/putuser.S:94
Code: 66 89 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90007587a58 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000000180
RDX: 0000000000000000 RSI: ffffffff8d7bfebf RDI: ffffffff8ba67000
RBP: ffffc90007587c10 R08: ffffffff821253df R09: ffff888037cf51b0
R10: dffffc0000000000 R11: ffffed1007c52de7 R12: 0000000000000000
R13: 1ffff92000eb0f50 R14: 0000200000000180 R15: 0000000000000000
 ioctl_fibmap fs/ioctl.c:90 [inline]
 file_ioctl+0x760/0x870 fs/ioctl.c:326
 do_vfs_ioctl+0xc29/0x1540 fs/ioctl.c:576
 __do_sys_ioctl fs/ioctl.c:595 [inline]
 __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
 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: 0033:0x7fd4e055c799
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:00007fd4de7b6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd4e07d5fa0 RCX: 00007fd4e055c799
RDX: 0000200000000180 RSI: 0000000000000001 RDI: 0000000000000005
RBP: 00007fd4e05f2c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd4e07d6038 R14: 00007fd4e07d5fa0 R15: 00007ffcfbbe06e8
 </TASK>
----------------
Code disassembly (best guess):
   0:	66 89 01             	mov    %ax,(%rcx)
   3:	31 c9                	xor    %ecx,%ecx
   5:	0f 01 ca             	clac
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	48 89 cb             	mov    %rcx,%rbx
  20:	48 c1 fb 3f          	sar    $0x3f,%rbx
  24:	48 09 d9             	or     %rbx,%rcx
  27:	0f 01 cb             	stac
* 2a:	89 01                	mov    %eax,(%rcx) <-- trapping instruction
  2c:	31 c9                	xor    %ecx,%ecx
  2e:	0f 01 ca             	clac
  31:	c3                   	ret
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop