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BUG: KCSAN: data-race in __put_unused_fd / do_select

write to 0xffff8880a3953e80 of 8 bytes by task 17752 on cpu 0:
 __clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:45 [inline]
 __clear_open_fd fs/file.c:249 [inline]
 __put_unused_fd+0x7b/0x120 fs/file.c:552
 put_unused_fd+0x51/0x70 fs/file.c:561
 do_sys_open+0x4e0/0x4f0 fs/open.c:1099
 __do_sys_openat fs/open.c:1124 [inline]
 __se_sys_openat fs/open.c:1118 [inline]
 __x64_sys_openat+0x62/0x80 fs/open.c:1118
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a3953e80 of 8 bytes by task 17754 on cpu 1:
 max_select_fd fs/select.c:446 [inline]
 do_select+0x315/0x1020 fs/select.c:487
 core_sys_select+0x312/0x650 fs/select.c:677
 do_pselect.constprop.0+0x11d/0x160 fs/select.c:759
 __do_sys_pselect6 fs/select.c:784 [inline]
 __se_sys_pselect6 fs/select.c:769 [inline]
 __x64_sys_pselect6+0x12e/0x170 fs/select.c:769
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17754 Comm: syz-executor.4 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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