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BUG: KCSAN: data-race in css_set_move_task / do_nanosleep

read to 0xffff8880ba6530e4 of 4 bytes by task 9084 on cpu 0:
 css_set_move_task+0x21e/0x4b0 kernel/cgroup/cgroup.c:905
 cgroup_migrate_execute+0x273/0x9b0 kernel/cgroup/cgroup.c:2500
 cgroup_update_dfl_csses+0x33c/0x350 kernel/cgroup/cgroup.c:2969
 cgroup_apply_control kernel/cgroup/cgroup.c:3209 [inline]
 cgroup_apply_control+0x47/0x60 kernel/cgroup/cgroup.c:3194
 cgroup_subtree_control_write+0x598/0x760 kernel/cgroup/cgroup.c:3358
 cgroup_file_write+0x119/0x320 kernel/cgroup/cgroup.c:3755
 kernfs_fop_write+0x1f4/0x2e0 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/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880ba6530e4 of 4 bytes by task 7609 on cpu 1:
 freezer_do_not_count include/linux/freezer.h:109 [inline]
 freezable_schedule include/linux/freezer.h:171 [inline]
 do_nanosleep+0x127/0x320 kernel/time/hrtimer.c:1871
 hrtimer_nanosleep+0x191/0x320 kernel/time/hrtimer.c:1924
 __do_sys_nanosleep kernel/time/hrtimer.c:1958 [inline]
 __se_sys_nanosleep kernel/time/hrtimer.c:1945 [inline]
 __x64_sys_nanosleep+0x106/0x150 kernel/time/hrtimer.c:1945
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7609 Comm: syz-executor.5 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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