[syzbot] [fs?] [mm?] WARNING in sched_mm_cid_fork

[syzbot <syzbot+9ca2c6e6b098bf5ae60a@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    7d31f578f323 Add linux-next specific files for 20251128
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=165b14b4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6336d8e94a7c517d
dashboard link: https://syzkaller.appspot.com/bug?extid=9ca2c6e6b098bf5ae60a
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=104a30c2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6b49d8ad90de/disk-7d31f578.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dbe2d4988ca7/vmlinux-7d31f578.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0448ab2411/bzImage-7d31f578.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9ca2c6e6b098bf5ae60a@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: kernel/sched/core.c:10573 at sched_mm_cid_fork+0x66/0xc30 kernel/sched/core.c:10573, CPU#0: kworker/u8:4/6077
Modules linked in:
CPU: 0 UID: 0 PID: 6077 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:sched_mm_cid_fork+0x66/0xc30 kernel/sched/core.c:10573
Code: 4c 8b 3b 4d 85 ff 74 21 49 8d 9d d4 15 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 13 0a 00 00 31 c0 3b 03 70 04 90 <0f> 0b 90 49 8d 9f 00 01 00 00 49 8d bf c0 01 00 00 48 89 7c 24 20
RSP: 0018:ffffc90003167bd8 EFLAGS: 00010246
RAX: 1ffff1100584e853 RBX: ffff88802c274298 RCX: ffff88802c273d00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88802c273d00
RBP: ffffc90003167d68 R08: ffffffff8e093e83 R09: 1ffffffff1c127d0
R10: dffffc0000000000 R11: fffffbfff1c127d1 R12: ffff88802c273d00
R13: ffff88802c273d00 R14: dffffc0000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcc18973e9c CR3: 000000003470a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 bprm_execve+0xd88/0x1400 fs/exec.c:1776
 kernel_execve+0x8f0/0x9f0 fs/exec.c:1919
 call_usermodehelper_exec_async+0x210/0x360 kernel/umh.c:109
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>


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