syzbot

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BUG: KCSAN: data-race in cgroup_freezer_migrate_task / handle_mm_fault

write to 0xffff88811bdca648 of 2 bytes by task 30125 on cpu 0:
 mem_cgroup_enter_user_fault include/linux/memcontrol.h:1905 [inline]
 handle_mm_fault+0x1f6/0x2be0 mm/memory.c:6480
 do_user_addr_fault+0x630/0x1080 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:618

read to 0xffff88811bdca648 of 2 bytes by task 16471 on cpu 1:
 cgroup_freezer_migrate_task+0xac/0x290 kernel/cgroup/freezer.c:242
 cgroup_migrate_execute+0x288/0x7f0 kernel/cgroup/cgroup.c:2735
 cgroup_update_dfl_csses kernel/cgroup/cgroup.c:3242 [inline]
 cgroup_apply_control+0x3ab/0x410 kernel/cgroup/cgroup.c:3482
 cgroup_subtree_control_write+0x7d5/0xb80 kernel/cgroup/cgroup.c:3627
 cgroup_file_write+0x197/0x350 kernel/cgroup/cgroup.c:4312
 kernfs_fop_write_iter+0x1eb/0x300 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x52a/0x960 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+0x2802/0x3000 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: 0x0001 -> 0x0061

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 16471 Comm: syz.3.13949 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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