CVE-2022-50819 udmabuf: Set ubuf->sg = NULL if the creation of sg table fails

In the Linux kernel, the following vulnerability has been resolved: udmabuf: Set ubuf-sg = NULL if the creation of sg table fails When userspace tries to map the dmabuf and if for some reason e.g. OOM the creation of the sg table fails, ubuf-sg needs to be set to NULL. Otherwise, when the userspa...