other: 0.782 semantic: 0.709 performance: 0.698 device: 0.652 graphic: 0.641 vnc: 0.511 PID: 0.506 files: 0.503 network: 0.484 socket: 0.466 boot: 0.391 debug: 0.375 permissions: 0.249 KVM: 0.164 Bad check for return value of mmap() In ./roms/skiboot/extract-gcov.c there is this code: addr = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0); assert(addr != NULL); This check is wrong, mmap never returns NULL, on errors it returns MAP_FAILED (or -1). (Also sidenote: asserts usually shouldn't be used for error checking.) In roms/skiboot/libstb/print-container.c there's a similar issue: payload = mmap(NULL, payload_st.st_size - SECURE_BOOT_HEADERS_SIZE, PROT_READ, MAP_PRIVATE, fdin, SECURE_BOOT_HEADERS_SIZE); if (!payload) This if should be (payload == MAP_FAILED). Another one is in ./roms/skiboot/libstb/create-container.c And in ./roms/u-boot/tools/aisimage.c there's an mmap call that does not check the return value at all. skiboot is a separate project, we do not manage its code in the QEMU project, but just include the source code in our release tarballs since we ship the skiboot binary with QEMU. Please report these problems to the skiboot project instead: https://github.com/open-power/skiboot And concerning the mmap in roms/u-boot/, please report that issue to the U-Boot project instead: https://www.denx.de/wiki/U-Boot/