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BUG: KCSAN: data-race in __d_instantiate / lookup_fast

read-write to 0xffff88815c03eb40 of 4 bytes by task 25059 on cpu 1:
 __d_instantiate+0x2cd/0x3b0 fs/dcache.c:2011
 d_instantiate_new+0x5c/0xf0 fs/dcache.c:2055
 ext4_mkdir+0x5e5/0x740 fs/ext4/namei.c:3025
 vfs_mkdir+0x1ac/0x2b0 fs/namei.c:4038
 do_mkdirat+0xf9/0x260 fs/namei.c:4061
 __do_sys_mkdir fs/namei.c:4081 [inline]
 __se_sys_mkdir fs/namei.c:4079 [inline]
 __x64_sys_mkdir+0x44/0x50 fs/namei.c:4079
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88815c03eb40 of 4 bytes by task 25061 on cpu 0:
 d_revalidate fs/namei.c:856 [inline]
 lookup_fast+0xd9/0x290 fs/namei.c:1635
 walk_component fs/namei.c:1990 [inline]
 link_path_walk+0x3f4/0x7e0 fs/namei.c:2321
 path_parentat fs/namei.c:2522 [inline]
 filename_parentat+0x115/0x380 fs/namei.c:2545
 do_unlinkat+0x9f/0x4f0 fs/namei.c:4289
 __do_sys_unlink fs/namei.c:4364 [inline]
 __se_sys_unlink fs/namei.c:4362 [inline]
 __x64_sys_unlink+0x30/0x40 fs/namei.c:4362
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00280000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25061 Comm: syz-executor.1 Not tainted 6.3.0-rc6-syzkaller-00046-gde4664485abb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
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