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BUG: KCSAN: data-race in d_delete / lookup_fast

read to 0xffff8881256bae40 of 4 bytes by task 3902 on cpu 1:
 d_is_miss include/linux/dcache.h:394 [inline]
 d_is_negative include/linux/dcache.h:440 [inline]
 lookup_fast+0xdf/0x700 fs/namei.c:1575
 walk_component+0x6d/0xe70 fs/namei.c:1796
 lookup_last fs/namei.c:2263 [inline]
 path_lookupat.isra.0+0x13a/0x5a0 fs/namei.c:2308
 filename_lookup+0x145/0x2b0 fs/namei.c:2338
 user_path_at_empty+0x4c/0x70 fs/namei.c:2598
 do_readlinkat+0x84/0x220 fs/stat.c:399
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881256bae40 of 4 bytes by task 7738 on cpu 0:
 d_delete fs/dcache.c:2448 [inline]
 d_delete+0xcc/0xe0 fs/dcache.c:2438
 vfs_unlink+0x398/0x3e0 fs/namei.c:4005
 do_unlinkat+0x32b/0x530 fs/namei.c:4055
 __do_sys_unlink fs/namei.c:4102 [inline]
 __se_sys_unlink fs/namei.c:4100 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4100
 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: 0 PID: 7738 Comm: udevd Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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