------------[ cut here ]------------
WARNING: CPU: 0 PID: 4534 at fs/iomap/buffered-io.c:975 iomap_page_mkwrite_iter fs/iomap/buffered-io.c:975 [inline]
WARNING: CPU: 0 PID: 4534 at fs/iomap/buffered-io.c:975 iomap_page_mkwrite+0x482/0x5d0 fs/iomap/buffered-io.c:998
Modules linked in:
CPU: 0 PID: 4534 Comm: syz.0.52 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:iomap_page_mkwrite_iter fs/iomap/buffered-io.c:975 [inline]
RIP: 0010:iomap_page_mkwrite+0x482/0x5d0 fs/iomap/buffered-io.c:998
Code: 80 3c 08 00 74 08 4c 89 f7 e8 0a 3e d9 ff 4d 8b 36 4c 89 f6 48 83 e6 04 31 ff e8 39 d9 94 ff 49 83 e6 04 75 3c e8 4e d5 94 ff <0f> 0b eb 38 48 89 df 4c 89 f6 44 89 e2 31 c9 4d 89 e8 e8 37 28 f3
RSP: 0018:ffffc9000420f560 EFLAGS: 00010283
RAX: ffffffff81e2f6c2 RBX: ffffea00016bf3c0 RCX: 0000000000080000
RDX: ffffc90005eaa000 RSI: 0000000000003436 RDI: 0000000000003437
RBP: ffffc9000420f710 R08: dffffc0000000000 R09: fffff940002d7e79
R10: fffff940002d7e79 R11: 1ffffd40002d7e78 R12: 0000000000001000
R13: ffffc9000420f5e8 R14: 0000000000000000 R15: ffffc9000420f5c0
FS:  00007f83419096c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f3a159198 CR3: 000000007d131000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __xfs_filemap_fault+0x353/0x8d0 fs/xfs/xfs_file.c:1346
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 wp_page_shared+0x16b/0x6d0 mm/memory.c:3259
 handle_pte_fault mm/memory.c:4668 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1ec7/0x43b0 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 0f 01 cb 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 89 d1 83 f8
RSP: 0018:ffffc9000420fbe0 EFLAGS: 00050206
RAX: ffffffff83dae101 RBX: 0000000000300000 RCX: 00000000002fe0c0
RDX: 0000000000300000 RSI: ffffc900042b2f40 RDI: 0000200000002000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff520008b6200
R10: 0000000000000000 R11: 0000000000060000 R12: 00007ffffffff000
R13: 00002000003000c0 R14: ffffc900042b1000 R15: 00002000000000c0
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 _copy_to_user+0xf0/0x130 lib/usercopy.c:40
 copy_to_user include/linux/uaccess.h:200 [inline]
 fb_read_screen_buffer drivers/gpu/drm/drm_fb_helper.c:2145 [inline]
 drm_fbdev_fb_read+0x2e4/0x580 drivers/gpu/drm/drm_fb_helper.c:2173
 do_loop_readv_writev fs/read_write.c:-1 [inline]
 do_iter_read+0x53e/0x7c0 fs/read_write.c:792
 vfs_readv fs/read_write.c:910 [inline]
 do_readv+0x237/0x3e0 fs/read_write.c:947
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f83436c3749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8341909038 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007f834391a090 RCX: 00007f83436c3749
RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 000000000000000a
RBP: 00007f8343747f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f834391a128 R14: 00007f834391a090 R15: 00007ffd18d33e68
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 d1                	mov    %edx,%ecx
   2:	c1 e9 03             	shr    $0x3,%ecx
   5:	83 e2 07             	and    $0x7,%edx
   8:	f3 48 a5             	rep movsq %ds:(%rsi),%es:(%rdi)
   b:	89 d1                	mov    %edx,%ecx
   d:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi)
   f:	31 c0                	xor    %eax,%eax
  11:	0f 01 ca             	clac
  14:	c3                   	ret
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	0f 01 cb             	stac
  1f:	83 fa 40             	cmp    $0x40,%edx
  22:	0f 82 70 ff ff ff    	jb     0xffffff98
  28:	89 d1                	mov    %edx,%ecx
* 2a:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2c:	31 c0                	xor    %eax,%eax
  2e:	0f 01 ca             	clac
  31:	c3                   	ret
  32:	90                   	nop
  33:	90                   	nop
  34:	90                   	nop
  35:	90                   	nop
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	89 d1                	mov    %edx,%ecx
  3e:	83                   	.byte 0x83
  3f:	f8                   	clc