syzbot

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BUG: KCSAN: data-race in d_lru_add / step_into

write to 0xffff888135928540 of 4 bytes by task 3668 on cpu 1:
 d_lru_add+0x45/0xe0 fs/dcache.c:427
 retain_dentry+0x153/0x190 fs/dcache.c:685
 dput+0x10e/0x1f0 fs/dcache.c:908
 done_path_create fs/namei.c:3833 [inline]
 do_mkdirat+0x10b/0x270 fs/namei.c:4041
 __do_sys_mkdir fs/namei.c:4058 [inline]
 __se_sys_mkdir fs/namei.c:4056 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:4056
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888135928540 of 4 bytes by task 3669 on cpu 0:
 __follow_mount_rcu fs/namei.c:1480 [inline]
 handle_mounts fs/namei.c:1531 [inline]
 step_into+0xdc/0x7d0 fs/namei.c:1831
 walk_component+0x164/0x230 fs/namei.c:1999
 lookup_last fs/namei.c:2450 [inline]
 path_lookupat+0x11d/0x2b0 fs/namei.c:2474
 filename_lookup+0x133/0x310 fs/namei.c:2503
 user_path_at_empty+0x3e/0x110 fs/namei.c:2876
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3380 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x24d/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00200000 -> 0x00280040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3669 Comm: syz-executor.4 Tainted: G        W          6.0.0-rc5-syzkaller-00017-gd1221cea11fc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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