CVE-2021-47579

In the Linux kernel, the following vulnerability has been resolved: ovl: fix warning in ovl_create_real() Syzbot triggered the following warning in ovl_workdir_create() -> ovl_create_real(): if (!err && WARN_ON(!newdentry->d_inode)) { The reason is that the cgroup2 filesystem returns from mkdir without instantiating the new dentry. Weird filesystems such as this will be rejected by overlayfs at a later stage during setup, but to prevent such a warning, call ovl_mkdir_real() directly from ovl_workdir_create() and reject this case early.

• linux linux kernel (< 4.19.222) • linux linux kernel (>= 4.20 < 5.4.168) • linux linux kernel (>= 5.5 < 5.10.88) • linux linux kernel (>= 5.11 < 5.15.11)