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BUG: KCSAN: data-race in __d_instantiate / step_into

write to 0xffff88813e105e70 of 8 bytes by task 9807 on cpu 0:
 __d_set_inode_and_type fs/dcache.c:344 [inline]
 __d_instantiate+0x1f9/0x3b0 fs/dcache.c:1853
 d_instantiate_new+0x5c/0xf0 fs/dcache.c:1899
 ext4_mkdir+0x5e5/0x740 fs/ext4/namei.c:3048
 vfs_mkdir+0x1ef/0x2f0 fs/namei.c:4122
 do_mkdirat+0x12f/0x2a0 fs/namei.c:4145
 __do_sys_mkdir fs/namei.c:4165 [inline]
 __se_sys_mkdir fs/namei.c:4163 [inline]
 __x64_sys_mkdir+0x44/0x50 fs/namei.c:4163
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813e105e70 of 8 bytes by task 9808 on cpu 1:
 step_into+0x123/0x800 fs/namei.c:1843
 walk_component+0x164/0x230 fs/namei.c:2007
 lookup_last fs/namei.c:2458 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2482
 filename_lookup+0x126/0x300 fs/namei.c:2511
 user_path_at_empty+0x42/0x110 fs/namei.c:2920
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3689 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x24b/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000000 -> 0xffff888171156118

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9808 Comm: syz-executor.0 Not tainted 6.7.0-syzkaller-12377-g9d1694dc91ce #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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