kernel: vmwgfx: use-after-free in vmw_execbuf_tie_context

A use-after-free vulnerability was found in the Linux kernel's vmwgfx driver in vmwexecbuftiecontext. This flaw allows a local, unprivileged attacker with access to either /dev/dri/card0 or /dev/dri/rendererD128, who can issue an ioctl on the resulting file descriptor, to crash the system, causin...