syzbot

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

read to 0xffff88812194a558 of 1 bytes by task 12818 on cpu 0:
 cgroup_freezer_migrate_task+0x131/0x1d0 kernel/cgroup/freezer.c:239
 cgroup_migrate_execute+0x32f/0xa30 kernel/cgroup/cgroup.c:2431
 cgroup_update_dfl_csses+0x33c/0x350 kernel/cgroup/cgroup.c:2913
 cgroup_apply_control kernel/cgroup/cgroup.c:3153 [inline]
 cgroup_apply_control+0x47/0x60 kernel/cgroup/cgroup.c:3138
 cgroup_subtree_control_write+0x598/0x760 kernel/cgroup/cgroup.c:3302
 cgroup_file_write+0x119/0x320 kernel/cgroup/cgroup.c:3699
 kernfs_fop_write+0x1bd/0x300 fs/kernfs/file.c:315
 __vfs_write+0x67/0xc0 fs/read_write.c:494
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812194a558 of 1 bytes by task 12810 on cpu 1:
 mem_cgroup_enter_user_fault include/linux/memcontrol.h:553 [inline]
 handle_mm_fault+0x34d/0x530 mm/memory.c:4107
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x456/0x8d0 arch/x86/mm/fault.c:1506
 do_page_fault+0x38/0x194 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12810 Comm: syz-executor.4 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================