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BUG: KCSAN: data-race in lookup_fast / shrink_dentry_list

write to 0xffff88812d8ca780 of 4 bytes by task 4871 on cpu 1:
 d_lru_del fs/dcache.c:410 [inline]
 __dput_to_list fs/dcache.c:898 [inline]
 shrink_dentry_list+0x352/0x590 fs/dcache.c:1147
 shrink_dcache_parent+0x4d/0x3c0 fs/dcache.c:1575
 d_invalidate+0x70/0x1b0 fs/dcache.c:1684
 lookup_fast+0x2ed/0x370 fs/namei.c:1509
 walk_component+0x5c/0x350 fs/namei.c:1857
 lookup_last fs/namei.c:2312 [inline]
 path_lookupat+0x11d/0x550 fs/namei.c:2336
 filename_lookup+0xf2/0x380 fs/namei.c:2369
 user_path_at_empty+0x3b/0x50 fs/namei.c:2649
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x90/0x270 fs/stat.c:185
 vfs_fstatat fs/stat.c:207 [inline]
 vfs_lstat include/linux/fs.h:3122 [inline]
 __do_sys_newlstat fs/stat.c:362 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:356
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:356
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812d8ca780 of 4 bytes by task 31058 on cpu 0:
 d_revalidate fs/namei.c:767 [inline]
 lookup_fast+0x7b/0x370 fs/namei.c:1505
 walk_component+0x5c/0x350 fs/namei.c:1857
 link_path_walk+0x471/0x730 fs/namei.c:2182
 path_openat+0x19f/0x20a0 fs/namei.c:3367
 do_filp_open+0xbd/0x1d0 fs/namei.c:3398
 do_sys_openat2+0xa3/0x240 fs/open.c:1172
 do_sys_open fs/open.c:1188 [inline]
 __do_sys_open fs/open.c:1196 [inline]
 __se_sys_open fs/open.c:1192 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1192
 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: 0 PID: 31058 Comm: systemd-udevd Not tainted 5.11.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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