[moderation] [cgroups?] KCSAN: data-race in cgroup_freezer_migrate_task / handle_mm_fault (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b290aae788e Merge tag 'sysctl-6.17-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=128e89bc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fb0f7e9c3b90e79f
dashboard link: https://syzkaller.appspot.com/bug?extid=304c2b36a6a4bac6024b
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [cgr...@vger.kernel.org han...@cmpxchg.org linux-...@vger.kernel.org mko...@suse.com t...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4dd30bbcf8b1/disk-4b290aae.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e743bc007946/vmlinux-4b290aae.xz
kernel image: https://storage.googleapis.com/syzbot-assets/36356550c456/bzImage-4b290aae.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+304c2b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in cgroup_freezer_migrate_task / handle_mm_fault

read-write to 0xffff888117d8c748 of 2 bytes by task 3529 on cpu 0:
lru_gen_exit_fault mm/memory.c:6310 [inline]
handle_mm_fault+0x206f/0x2be0 mm/memory.c:6407
do_user_addr_fault+0x636/0x1090 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff888117d8c748 of 2 bytes by task 3528 on cpu 1:
cgroup_freezer_migrate_task+0xac/0x290 kernel/cgroup/freezer.c:236
cgroup_migrate_execute+0x288/0x7f0 kernel/cgroup/cgroup.c:2647
cgroup_update_dfl_csses kernel/cgroup/cgroup.c:3135 [inline]
cgroup_apply_control+0x3ab/0x410 kernel/cgroup/cgroup.c:3375
cgroup_subtree_control_write+0x7d5/0xb80 kernel/cgroup/cgroup.c:3520
cgroup_file_write+0x197/0x350 kernel/cgroup/cgroup.c:4183
kernfs_fop_write_iter+0x1be/0x2d0 fs/kernfs/file.c:334
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x49d/0x8e0 fs/read_write.c:686
ksys_write+0xda/0x1a0 fs/read_write.c:738
__do_sys_write fs/read_write.c:749 [inline]
__se_sys_write fs/read_write.c:746 [inline]
__x64_sys_write+0x40/0x50 fs/read_write.c:746
x64_sys_call+0x27fe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0061 -> 0x0001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3528 Comm: syz.7.7809 Not tainted 6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.