[syzbot] [kernel?] WARNING in comedi_compat_ioctl

[syzbot <syzbot+6048f8e5da91c7055339@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    3f31a806a62e Merge tag 'mm-hotfixes-stable-2025-07-11-16-1..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=152307d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=84eae426cbd8669c
dashboard link: https://syzkaller.appspot.com/bug?extid=6048f8e5da91c7055339
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3f31a806.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/51112e82d2bc/vmlinux-3f31a806.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dfafec79e704/bzImage-3f31a806.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6048f8e5da91c7055339@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6660 at mm/page_alloc.c:4935 __alloc_frozen_pages_noprof+0x30b/0x23f0 mm/page_alloc.c:4935
Modules linked in:
CPU: 0 UID: 0 PID: 6660 Comm: syz.2.103 Not tainted 6.16.0-rc5-syzkaller-00266-g3f31a806a62e #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
RIP: 0010:__alloc_frozen_pages_noprof+0x30b/0x23f0 mm/page_alloc.c:4935
Code: f0 5b 5d 41 5c 41 5d 41 5e 41 5f e9 8f 12 73 09 83 fe 0a 0f 86 0a fe ff ff 80 3d 17 9d 7d 0e 00 75 0b c6 05 0e 9d 7d 0e 01 90 <0f> 0b 90 45 31 f6 eb 81 4d 85 f6 74 22 44 89 fa 89 ee 4c 89 f7 e8
RSP: 0018:ffffc9000dfe7988 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000001a RDI: 0000000000040dc0
RBP: 00000027fffffb00 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000001a
R13: 1ffff92001bfcf46 R14: 00000027fffffb00 R15: 000000000000001a
FS:  0000000000000000(0000) GS:ffff888097520000(0063) knlGS:00000000f503cb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7496188 CR3: 0000000066b87000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __alloc_pages_noprof+0xb/0x1b0 mm/page_alloc.c:4993
 __alloc_pages_node_noprof include/linux/gfp.h:284 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:311 [inline]
 ___kmalloc_large_node+0x84/0x1e0 mm/slub.c:4272
 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:4300
 __do_kmalloc_node mm/slub.c:4316 [inline]
 __kmalloc_noprof.cold+0xc/0x61 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 compat_insnlist drivers/comedi/comedi_fops.c:3145 [inline]
 comedi_compat_ioctl+0x3e9/0x910 drivers/comedi/comedi_fops.c:3225
 __do_compat_sys_ioctl fs/ioctl.c:1005 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:948 [inline]
 __ia32_compat_sys_ioctl+0x23f/0x370 fs/ioctl.c:948
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf708e579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f503c55c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000008008640b
RDX: 0000000080000080 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup