In the Linux kernel, the following vulnerability has been resolved: ovl: fix UAF in ovl_do_mkdir...

In the Linux kernel, the following vulnerability has been resolved:

ovl: fix UAF in ovl_do_mkdir() debug print

ovl_do_mkdir() prints the input dentry with %pd after vfs_mkdir(). Since commit fe497f0759e0 ("VFS: change vfs_mkdir() to unlock on failure."), vfs_mkdir() calls end_creating() on the input dentry on failure and may replace it on success, so the post-call %pd can use-after-free the dentry when CONFIG_OVERLAY_FS_DEBUG is enabled.

Print the dentry before the call and only the result afterward.