[PATCH] xl: avoid (another) uninitialised use of rc in vcpuset()

[PATCH] xl: avoid (another) uninitialised use of rc in vcpuset()

[Dario Faggioli]

Rearange the case when we check the new number of vCPUs
against the number of host pCPUs not to use rc for internal
error reporting. In fact:
 - rc was at risk of being used uninitialised;
 - rc should only be used for holding libxl error codes.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
---
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Harmandeep Kaur <write.harmandeep@gmail.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
---
 tools/libxl/xl_cmdimpl.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 9b6b42c..78048a1 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -5457,21 +5457,21 @@ static int vcpuset(uint32_t domid, const char* nr_vcpus, int check_host)
      * by the host's amount of pCPUs.
      */
     if (check_host) {
-        unsigned int host_cpu = libxl_get_max_cpus(ctx);
+        unsigned int online_vcpus, host_cpu = libxl_get_max_cpus(ctx);
         libxl_dominfo dominfo;
 
         if (libxl_domain_info(ctx, &dominfo, domid))
             return 1;
 
-        if (max_vcpus > dominfo.vcpu_online && max_vcpus > host_cpu) {
+        online_vcpus = dominfo.vcpu_online;
+        libxl_dominfo_dispose(&dominfo);
+
+        if (max_vcpus > online_vcpus && max_vcpus > host_cpu) {
             fprintf(stderr, "You are overcommmitting! You have %d physical" \
                     " CPUs and want %d vCPUs! Aborting, use --ignore-host to" \
                     " continue\n", host_cpu, max_vcpus);
-            rc = 1;
-        }
-        libxl_dominfo_dispose(&dominfo);
-        if (rc)
             return 1;
+        }
     }
     rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
     if (rc) {

Re: [PATCH] xl: avoid (another) uninitialised use of rc in vcpuset()

[Ian Campbell]

On Wed, 2015-11-04 at 13:03 +0100, Dario Faggioli wrote:
> Rearange the case when we check the new number of vCPUs
> against the number of host pCPUs not to use rc for internal
> error reporting. In fact:
>  - rc was at risk of being used uninitialised;
>  - rc should only be used for holding libxl error codes.
> 
> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>

acked + applied.

> ---
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Wei Liu <wei.liu2@citrix.com>
> Cc: Harmandeep Kaur <write.harmandeep@gmail.com>
> Cc: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
>  tools/libxl/xl_cmdimpl.c |   12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 9b6b42c..78048a1 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -5457,21 +5457,21 @@ static int vcpuset(uint32_t domid, const char*
> nr_vcpus, int check_host)
>       * by the host's amount of pCPUs.
>       */
>      if (check_host) {
> -        unsigned int host_cpu = libxl_get_max_cpus(ctx);
> +        unsigned int online_vcpus, host_cpu = libxl_get_max_cpus(ctx);
>          libxl_dominfo dominfo;
>  
>          if (libxl_domain_info(ctx, &dominfo, domid))
>              return 1;
>  
> -        if (max_vcpus > dominfo.vcpu_online && max_vcpus > host_cpu) {
> +        online_vcpus = dominfo.vcpu_online;
> +        libxl_dominfo_dispose(&dominfo);
> +
> +        if (max_vcpus > online_vcpus && max_vcpus > host_cpu) {
>              fprintf(stderr, "You are overcommmitting! You have %d
> physical" \
>                      " CPUs and want %d vCPUs! Aborting, use --ignore-
> host to" \
>                      " continue\n", host_cpu, max_vcpus);
> -            rc = 1;
> -        }
> -        libxl_dominfo_dispose(&dominfo);
> -        if (rc)
>              return 1;
> +        }
>      }
>      rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
>      if (rc) {
> 
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