misc: pci_endpoint_test: Fix pci_endpoint_test_{copy,write,read}() panic
In the Linux kernel, the following vulnerability has been resolved: misc: pci_endpoint_test: Fix pci_endpoint_test_{copy,write,read}() panic The dma_map_single() doesn't permit zero length mapping. It causes a follow panic. A panic was reported on arm64: [ 60.137988] ------------[ cut here ]------------ [ 60.142630] kernel BUG at kernel/dma/swiotlb.c:624! [ 60.147508] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 60.152992] Modules linked in: dw_hdmi_cec crct10dif_ce simple_bridge rcar_fdp1 vsp1 rcar_vin videobuf2_vmalloc rcar_csi2 v4l 2_mem2mem videobuf2_dma_contig videobuf2_memops pci_endpoint_test videobuf2_v4l2 videobuf2_co