In the Linux kernel, the following vulnerability has been resolved:
dmaengine: at_xdmac: avoid null_prt_deref in at_xdmac_prep_dma_memset
The at_xdmac_memset_create_desc may return NULL, which will lead to a
null pointer dereference. For example, the len input is error, or the
atchan->free_descs_list is empty and memory is exhausted. Therefore, add
check to avoid this.
