syzbot

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BUG: KCSAN: data-race in attach_to_pi_owner / futex_wait_queue_me

read-write to 0xffff88810a498064 of 4 bytes by task 23559 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 futex_wait_queue_me+0x198/0x240 kernel/futex.c:2588
 futex_wait_requeue_pi kernel/futex.c:3224 [inline]
 do_futex+0x1838/0x2120 kernel/futex.c:3769
 __do_sys_futex kernel/futex.c:3810 [inline]
 __se_sys_futex+0x26d/0x330 kernel/futex.c:3778
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3778
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810a498064 of 4 bytes by task 23574 on cpu 1:
 attach_to_pi_owner+0x64/0x480 kernel/futex.c:1215
 lookup_pi_state kernel/futex.c:1302 [inline]
 futex_requeue+0xb32/0x14d0 kernel/futex.c:2045
 do_futex+0x11d3/0x2120 kernel/futex.c:3772
 __do_sys_futex kernel/futex.c:3810 [inline]
 __se_sys_futex+0x26d/0x330 kernel/futex.c:3778
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3778
 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: 23574 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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