Describe CVE-2021-47420.
What is CVE-2021-47420?
In the Linux kernel, the following vulnerability has been resolved:

drm/amdkfd: fix a potential ttm->sg memory leak

Memory is allocated for ttm->sg by kmalloc in kfd_mem_dmamap_userptr,
but isn't freed by kfree in kfd_mem_dmaunmap_userptr. Free it!.