[moderation] [mm?] KCSAN: data-race in copy_mm / lru_gen_del_mm (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 17e7b8eacf4c Merge tag 'cifs-fixes-7.3-rc4' of https://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d6c525580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8372e2cd52628d4f
dashboard link: https://syzkaller.appspot.com/bug?extid=d891521019f0c0cab15f
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [ak...@linux-foundation.org axelra...@google.com bao...@kernel.org da...@kernel.org han...@cmpxchg.org kas...@tencent.com linux-...@vger.kernel.org linu...@kvack.org l...@kernel.org mho...@kernel.org qi.z...@linux.dev shakee...@linux.dev wei...@google.com yua...@google.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/60ea54622289/disk-17e7b8ea.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/675e38c8bebf/vmlinux-17e7b8ea.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1006b8efd827/bzImage-17e7b8ea.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d89152...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in copy_mm / lru_gen_del_mm

write to 0xffff8881077eb088 of 8 bytes by task 7336 on cpu 0:
__list_del include/linux/list.h:241 [inline]
__list_del_entry include/linux/list.h:264 [inline]
list_del_init include/linux/list.h:333 [inline]
lru_gen_del_mm+0x299/0x3e0 mm/vmscan.c:2998
__mmput+0x17a/0x1c0 kernel/fork.c:1203
mmput+0x40/0x50 kernel/fork.c:1216
exit_mm+0x113/0x1a0 kernel/exit.c:617
do_exit+0x438/0x1510 kernel/exit.c:999
do_group_exit+0x138/0x140 kernel/exit.c:1154
__do_sys_exit_group kernel/exit.c:1165 [inline]
__se_sys_exit_group kernel/exit.c:1163 [inline]
__x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1163
x64_sys_call+0x254f/0x2550 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881077eaa00 of 1728 bytes by task 7337 on cpu 1:
dup_mm kernel/fork.c:1537 [inline]
copy_mm+0xd6/0x340 kernel/fork.c:1595
copy_process+0x10ad/0x2340 kernel/fork.c:2310
kernel_clone+0x1c0/0x5f0 kernel/fork.c:2769
__do_sys_clone kernel/fork.c:2911 [inline]
__se_sys_clone kernel/fork.c:2895 [inline]
__x64_sys_clone+0x143/0x180 kernel/fork.c:2895
x64_sys_call+0x2479/0x2550 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7337 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================


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