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BUG: KCSAN: data-race in __d_instantiate / lookup_fast

read-write to 0xffff8881092563c0 of 4 bytes by task 32743 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:3046
 vfs_mkdir+0x1ac/0x2b0 fs/namei.c:4115
 do_mkdirat+0xf9/0x260 fs/namei.c:4138
 __do_sys_mkdir fs/namei.c:4158 [inline]
 __se_sys_mkdir fs/namei.c:4156 [inline]
 __x64_sys_mkdir+0x44/0x50 fs/namei.c:4156
 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 0xffff8881092563c0 of 4 bytes by task 32754 on cpu 0:
 d_revalidate fs/namei.c:858 [inline]
 lookup_fast+0xd9/0x290 fs/namei.c:1639
 open_last_lookups fs/namei.c:3529 [inline]
 path_openat+0x446/0x1d00 fs/namei.c:3788
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_open fs/open.c:1380 [inline]
 __se_sys_open fs/open.c:1376 [inline]
 __x64_sys_open+0xe6/0x110 fs/open.c:1376
 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 -> 0x00280040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32754 Comm: syz-executor.1 Not tainted 6.4.0-rc2-syzkaller-00015-g1b66c114d161 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
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