==================================================================
BUG: KCSAN: data-race in __d_instantiate / lookup_fast

read-write to 0xffff8881067cd540 of 4 bytes by task 3909 on cpu 0:
 __d_instantiate+0x2cd/0x3c0 fs/dcache.c:1855
 d_instantiate_new+0x5c/0xf0 fs/dcache.c:1899
 ext4_add_nondir+0x16c/0x190 fs/ext4/namei.c:2798
 ext4_create+0x20e/0x2f0 fs/ext4/namei.c:2839
 vfs_create+0x194/0x280 fs/namei.c:3202
 do_mknodat+0x2a4/0x420 fs/namei.c:4054
 __do_sys_mknod fs/namei.c:4087 [inline]
 __se_sys_mknod fs/namei.c:4085 [inline]
 __x64_sys_mknod+0x53/0x60 fs/namei.c:4085
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881067cd540 of 4 bytes by task 3912 on cpu 1:
 d_revalidate fs/namei.c:861 [inline]
 lookup_fast+0xd9/0x290 fs/namei.c:1642
 walk_component+0x3f/0x230 fs/namei.c:2001
 lookup_last fs/namei.c:2462 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2486
 filename_lookup+0x126/0x300 fs/namei.c:2515
 user_path_at_empty+0x42/0x120 fs/namei.c:2924
 user_path_at include/linux/namei.h:57 [inline]
 path_getxattr+0x60/0x230 fs/xattr.c:785
 __do_sys_getxattr fs/xattr.c:800 [inline]
 __se_sys_getxattr fs/xattr.c:797 [inline]
 __x64_sys_getxattr+0x5b/0x70 fs/xattr.c:797
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000 -> 0x00480000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3912 Comm: syz-executor.2 Not tainted 6.8.0-rc7-syzkaller-00017-g29cd507cbec2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================