On Thu, 24 Oct 2019 at 16:19, Paolo Bonzini <pbonz...@redhat.com> wrote:
>
> From: Sergio Lopez <s...@redhat.com>
>
> microvm is a machine type inspired by Firecracker and constructed
> after its machine model.
>
> It's a minimalist machine type without PCI nor ACPI support, designed
> for short-lived guests. microvm also establishes a baseline for
> benchmarking and optimizing both QEMU and guest operating systems,
> since it is optimized for both boot time and footprint.
Hi; Coverity points out a memory leak in this commit
(CID 1407218):
> +static void microvm_fix_kernel_cmdline(MachineState *machine)
> +{
> + X86MachineState *x86ms = X86_MACHINE(machine);
> + BusState *bus;
> + BusChild *kid;
> + char *cmdline;
> +
> + /*
> + * Find MMIO transports with attached devices, and add them to the kernel
> + * command line.
> + *
> + * Yes, this is a hack, but one that heavily improves the UX without
> + * introducing any significant issues.
> + */
> + cmdline = g_strdup(machine->kernel_cmdline);
Here we allocate memory for cmdline...
> + bus = sysbus_get_default();
> + QTAILQ_FOREACH(kid, &bus->children, sibling) {
> + DeviceState *dev = kid->child;
> + ObjectClass *class = object_get_class(OBJECT(dev));
> +
> + if (class == object_class_by_name(TYPE_VIRTIO_MMIO)) {
> + VirtIOMMIOProxy *mmio = VIRTIO_MMIO(OBJECT(dev));
> + VirtioBusState *mmio_virtio_bus = &mmio->bus;
> + BusState *mmio_bus = &mmio_virtio_bus->parent_obj;
> +
> + if (!QTAILQ_EMPTY(&mmio_bus->children)) {
> + gchar *mmio_cmdline =
> microvm_get_mmio_cmdline(mmio_bus->name);
> + if (mmio_cmdline) {
> + char *newcmd = g_strjoin(NULL, cmdline, mmio_cmdline,
> NULL);
> + g_free(mmio_cmdline);
> + g_free(cmdline);
> + cmdline = newcmd;
> + }
> + }
> + }
> + }
> +
> + fw_cfg_modify_i32(x86ms->fw_cfg, FW_CFG_CMDLINE_SIZE, strlen(cmdline) +
> 1);
> + fw_cfg_modify_string(x86ms->fw_cfg, FW_CFG_CMDLINE_DATA, cmdline);
...but fw_cfg_modify_string() takes a copy of the string it's passed,
so we still have ownership of 'cmdline' and need to free it here
to avoid a leak.
> +}
thanks
-- PMM
