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BUG: KCSAN: data-race in __d_instantiate / lookup_fast

read-write to 0xffff88810ac71cc0 of 4 bytes by task 13253 on cpu 1:
 __d_instantiate+0x2cd/0x3b0 fs/dcache.c:2010
 d_instantiate_new+0x5c/0xf0 fs/dcache.c:2054
 ext4_add_nondir+0x16c/0x190 fs/ext4/namei.c:2797
 ext4_symlink+0x4dc/0x590 fs/ext4/namei.c:3433
 vfs_symlink+0xc2/0x1a0 fs/namei.c:4480
 do_symlinkat+0xe3/0x320 fs/namei.c:4506
 __do_sys_symlinkat fs/namei.c:4522 [inline]
 __se_sys_symlinkat fs/namei.c:4519 [inline]
 __x64_sys_symlinkat+0x62/0x70 fs/namei.c:4519
 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 0xffff88810ac71cc0 of 4 bytes by task 13258 on cpu 0:
 d_revalidate fs/namei.c:860 [inline]
 lookup_fast+0xd9/0x290 fs/namei.c:1642
 walk_component+0x3f/0x230 fs/namei.c:1997
 lookup_last fs/namei.c:2458 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2482
 do_o_path+0x44/0x120 fs/namei.c:3767
 path_openat+0x1a01/0x1d10 fs/namei.c:3789
 do_filp_open+0xf6/0x200 fs/namei.c:3823
 do_sys_openat2+0xab/0x110 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1448
 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 -> 0x00680000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13258 Comm: syz-executor.2 Not tainted 6.5.0-syzkaller-10204-gb84acc11b1c9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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