syzbot

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BUG: KCSAN: data-race in attach_to_pi_owner / futex_wait_queue_me

write to 0xffff8881023a60a4 of 4 bytes by task 28035 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 futex_wait_queue_me+0x1a2/0x290 kernel/futex.c:2627
 futex_wait_requeue_pi.constprop.0+0x2d0/0xa10 kernel/futex.c:3265
 do_futex+0x1cc/0x18d0 kernel/futex.c:3664
 __do_sys_futex kernel/futex.c:3705 [inline]
 __se_sys_futex kernel/futex.c:3673 [inline]
 __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3673
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881023a60a4 of 4 bytes by task 28038 on cpu 1:
 attach_to_pi_owner+0x83/0x420 kernel/futex.c:1250
 lookup_pi_state kernel/futex.c:1325 [inline]
 futex_requeue+0xfb9/0x12d0 kernel/futex.c:2069
 do_futex+0x2f7/0x18d0 kernel/futex.c:3667
 __do_sys_futex kernel/futex.c:3705 [inline]
 __se_sys_futex kernel/futex.c:3673 [inline]
 __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3673
 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: 28038 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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