Re: [Qemu-devel] [PATCH] vl: Fix compile issue with Werror option

[Markus Armbruster <armbru@redhat.com>]

Mike Qiu <qiudayu@linux.vnet.ibm.com> writes:

> Currently, if compile with Werror option, the error message shows
> below:
>
>   GEN   config-host.h
>   GEN   trace/generated-tracers.h
>         CHK version_gen.h
>   GEN   trace/generated-tracers.c
>   CC    vl.o
> vl.c: In function ‘get_boot_devices_list’:
> vl.c:1257:21: error: ‘bootpath’ may be used uninitialized
> 	in this function [-Werror=maybe-uninitialized]
>          len = strlen(bootpath) + 1;
>                      ^
> cc1: all warnings being treated as errors
> make: *** [vl.o] Error 1
>
> This patch is to solve this issue.
>
> Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
> ---
>  vl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/vl.c b/vl.c
> index b97728f..d67b284 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1230,7 +1230,7 @@ char *get_boot_devices_list(size_t *size, bool ignore_suffixes)
>      char *list = NULL;
>  
>      QTAILQ_FOREACH(i, &fw_boot_order, link) {
> -        char *devpath = NULL, *bootpath;
> +        char *devpath = NULL, *bootpath = NULL;
>          size_t len;
>  
>          if (i->dev) {

Compiler version?  I'm asking because bootpath looks quite defined on
all paths leading to the line you quoted:

    QTAILQ_FOREACH(i, &fw_boot_order, link) {
        char *devpath = NULL, *bootpath;
        size_t len;

        if (i->dev) {
            devpath = qdev_get_fw_dev_path(i->dev);
            assert(devpath);
        }

        if (i->suffix && devpath) {
            size_t bootpathlen = strlen(devpath) + strlen(i->suffix) + 1;

--->        bootpath = g_malloc(bootpathlen);
            snprintf(bootpath, bootpathlen, "%s%s", devpath, i->suffix);
            g_free(devpath);
        } else if (devpath) {
--->        bootpath = devpath;
        } else {
            assert(i->suffix);
--->        bootpath = g_strdup(i->suffix);
        }

        if (total) {
            list[total-1] = '\n';
        }
        len = strlen(bootpath) + 1;