==================================================================
BUG: KCSAN: data-race in __put_unused_fd / do_select

write to 0xffff88811fb77880 of 8 bytes by task 19906 on cpu 0:
 __clear_bit include/asm-generic/bitops-instrumented.h:76 [inline]
 __clear_open_fd fs/file.c:249 [inline]
 __put_unused_fd+0x7b/0x120 fs/file.c:552
 __close_fd+0xdc/0x140 fs/file.c:634
 __do_sys_close fs/open.c:1193 [inline]
 __se_sys_close fs/open.c:1191 [inline]
 __x64_sys_close+0x49/0xb0 fs/open.c:1191
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811fb77880 of 8 bytes by task 19908 on cpu 1:
 max_select_fd fs/select.c:446 [inline]
 do_select+0x315/0x1020 fs/select.c:487
 core_sys_select+0x381/0x550 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/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19908 Comm: syz-executor.1 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 19908 Comm: syz-executor.1 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x11d/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:315
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:423
 check_access kernel/kcsan/core.c:466 [inline]
 __tsan_read8 kernel/kcsan/core.c:596 [inline]
 __tsan_read8+0xc6/0x100 kernel/kcsan/core.c:596
 max_select_fd fs/select.c:446 [inline]
 do_select+0x315/0x1020 fs/select.c:487
 core_sys_select+0x381/0x550 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/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a669
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc8249f6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010e
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045a669
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000040
RBP: 000000000075bfc8 R08: 0000000020000200 R09: 0000000000000000
R10: 0000000020000140 R11: 0000000000000246 R12: 00007fc8249f76d4
R13: 00000000004c7f25 R14: 00000000004dde70 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..