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BUG: KCSAN: data-race in futex_wait_queue_me / kthread_is_per_cpu

write to 0xffff8881002e70ac of 4 bytes by task 7366 on cpu 1:
 freezer_do_not_count include/linux/freezer.h:109 [inline]
 freezable_schedule include/linux/freezer.h:171 [inline]
 futex_wait_queue_me+0x198/0x260 kernel/futex.c:2606
 futex_wait+0x143/0x430 kernel/futex.c:2708
 do_futex+0x9e8/0x1ee0 kernel/futex.c:3733
 __do_sys_futex kernel/futex.c:3796 [inline]
 __se_sys_futex+0x2a8/0x390 kernel/futex.c:3762
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3762
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881002e70ac of 4 bytes by interrupt on cpu 0:
 __to_kthread kernel/kthread.c:101 [inline]
 kthread_is_per_cpu+0x2d/0x80 kernel/kthread.c:540
 can_migrate_task+0xf/0x180 kernel/sched/fair.c:7615
 detach_tasks+0xab/0x380 kernel/sched/fair.c:7779
 load_balance+0x768/0xcc0 kernel/sched/fair.c:9679
 rebalance_domains+0x1ae/0x2d0 kernel/sched/fair.c:10058
 __do_softirq+0x12c/0x275 kernel/softirq.c:559
 invoke_softirq kernel/softirq.c:433 [inline]
 __irq_exit_rcu+0xa5/0xb0 kernel/softirq.c:637
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 smap_restore arch/x86/include/asm/smap.h:67 [inline]
 kcsan_setup_watchpoint+0x436/0x470 kernel/kcsan/core.c:595
 kernfs_refresh_inode fs/kernfs/inode.c:173 [inline]
 kernfs_iop_permission+0x57/0x180 fs/kernfs/inode.c:288
 do_inode_permission fs/namei.c:446 [inline]
 inode_permission+0x18c/0x290 fs/namei.c:513
 may_lookup fs/namei.c:1659 [inline]
 link_path_walk+0x1c2/0x780 fs/namei.c:2211
 path_lookupat+0x7b/0x570 fs/namei.c:2420
 filename_lookup+0xff/0x390 fs/namei.c:2454
 user_path_at_empty+0x3b/0x50 fs/namei.c:2734
 user_path_at include/linux/namei.h:60 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:203
 vfs_fstatat fs/stat.c:225 [inline]
 vfs_lstat include/linux/fs.h:3386 [inline]
 __do_sys_newlstat fs/stat.c:380 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:374
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:374
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1032 Comm: systemd-udevd Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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