syzbot

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BUG: KCSAN: data-race in attach_to_pi_owner / do_nanosleep

read-write to 0xffff88810941902c of 4 bytes by task 8451 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_nanosleep+0x111/0x3c0 kernel/time/hrtimer.c:1878
 hrtimer_nanosleep kernel/time/hrtimer.c:1931 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1965 [inline]
 __se_sys_nanosleep+0x20b/0x2a0 kernel/time/hrtimer.c:1952
 __x64_sys_nanosleep+0x2d/0x40 kernel/time/hrtimer.c:1952
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810941902c of 4 bytes by task 15666 on cpu 1:
 attach_to_pi_owner+0x64/0x480 kernel/futex.c:1215
 futex_lock_pi_atomic+0x338/0x4f0 kernel/futex.c:1420
 futex_lock_pi+0x2bf/0x880 kernel/futex.c:2797
 do_futex+0x1fc/0x20c0 kernel/futex.c:3776
 __do_sys_futex kernel/futex.c:3826 [inline]
 __se_sys_futex+0x2a8/0x390 kernel/futex.c:3792
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3792
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15666 Comm: syz-executor.4 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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