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BUG: KCSAN: data-race in __d_drop / dput

write to 0xffff888141245190 of 8 bytes by task 26025 on cpu 0:
 __d_drop+0x16a/0x240 fs/dcache.c:508
 d_invalidate+0x4c/0x1b0 fs/dcache.c:1730
 lookup_dcache fs/namei.c:1575 [inline]
 __lookup_hash+0x16c/0x180 fs/namei.c:1593
 filename_create+0x147/0x2b0 fs/namei.c:3703
 do_mkdirat+0x63/0x280 fs/namei.c:3946
 __do_sys_mkdir fs/namei.c:3977 [inline]
 __se_sys_mkdir fs/namei.c:3975 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3975
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888141245190 of 8 bytes by task 26026 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:332 [inline]
 fast_dput fs/dcache.c:837 [inline]
 dput+0xa4/0x1f0 fs/dcache.c:900
 handle_mounts fs/namei.c:1552 [inline]
 step_into+0x1c7/0x760 fs/namei.c:1850
 walk_component+0x19a/0x280 fs/namei.c:2026
 lookup_last fs/namei.c:2475 [inline]
 path_lookupat+0x11d/0x2b0 fs/namei.c:2499
 filename_lookup+0x130/0x310 fs/namei.c:2528
 user_path_at_empty+0x3e/0x110 fs/namei.c:2851
 user_path_at include/linux/namei.h:57 [inline]
 do_fchmodat fs/open.c:619 [inline]
 __do_sys_fchmodat fs/open.c:634 [inline]
 __se_sys_fchmodat fs/open.c:631 [inline]
 __x64_sys_fchmodat+0x83/0x110 fs/open.c:631
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888237ac5b30 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26026 Comm: syz-executor.2 Not tainted 5.18.0-rc4-syzkaller-00064-g8f4dd16603ce-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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