[PATCH v2] xl: initialise rc before using it in vcpuset

[PATCH v2] xl: initialise rc before using it in vcpuset

[Wei Liu]

In 5b725e56 (xl: improve return and exit codes of vcpu related
functions), the return value of libxl_cpu_bitmap_alloc was not stored in
rc anymore. Yet the subsequent fprintf still used that.

Reinstate the original implementation, that is, to store return value of
libxl_cpu_bitmap_alloc in rc before using rc.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Harmandeep Kaur <write.harmandeep@gmail.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>

v2: print rc.
---
 tools/libxl/xl_cmdimpl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 2756d2f..9b6b42c 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -5473,7 +5473,8 @@ static int vcpuset(uint32_t domid, const char* nr_vcpus, int check_host)
         if (rc)
             return 1;
     }
-    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus)) {
+    rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
+    if (rc) {
         fprintf(stderr, "libxl_cpu_bitmap_alloc failed, rc: %d\n", rc);
         return 1;
     }
-- 
2.1.4

Re: [PATCH v2] xl: initialise rc before using it in vcpuset

[Dario Faggioli]

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On Wed, 2015-11-04 at 11:32 +0000, Wei Liu wrote:

> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 2756d2f..9b6b42c 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -5473,7 +5473,8 @@ static int vcpuset(uint32_t domid, const char*
> nr_vcpus, int check_host)
>          if (rc)
>              return 1;
>      }
> -    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus)) {
> +    rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
> +    if (rc) {
>          fprintf(stderr, "libxl_cpu_bitmap_alloc failed, rc: %d\n",
> rc);
>          return 1;
>      }
>
Don't we also need to initialise rc to 0? It seems to me that it may be
used uninitialised also inside of if(check_host)...

Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: [PATCH v2] xl: initialise rc before using it in vcpuset

[Ian Campbell]

On Wed, 2015-11-04 at 12:38 +0100, Dario Faggioli wrote:
> On Wed, 2015-11-04 at 11:32 +0000, Wei Liu wrote:
> 
> > diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> > index 2756d2f..9b6b42c 100644
> > --- a/tools/libxl/xl_cmdimpl.c
> > +++ b/tools/libxl/xl_cmdimpl.c
> > @@ -5473,7 +5473,8 @@ static int vcpuset(uint32_t domid, const char*
> > nr_vcpus, int check_host)
> >          if (rc)
> >              return 1;
> >      }
> > -    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus)) {
> > +    rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
> > +    if (rc) {
> >          fprintf(stderr, "libxl_cpu_bitmap_alloc failed, rc: %d\n",
> > rc);
> >          return 1;
> >      }
> > 
> Don't we also need to initialise rc to 0? It seems to me that it may be
> used uninitialised also inside of if(check_host)...

Looks like it, a separate issue though.

Don't initialise rc to 0, add a suitable else though.

> 
> Regards,
> Dario
> 

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Re: [PATCH v2] xl: initialise rc before using it in vcpuset

[Dario Faggioli]

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On Wed, 2015-11-04 at 11:47 +0000, Ian Campbell wrote:
> On Wed, 2015-11-04 at 12:38 +0100, Dario Faggioli wrote:
> > On Wed, 2015-11-04 at 11:32 +0000, Wei Liu wrote:
> > 
> > > diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> > > index 2756d2f..9b6b42c 100644
> > > --- a/tools/libxl/xl_cmdimpl.c
> > > +++ b/tools/libxl/xl_cmdimpl.c
> > > @@ -5473,7 +5473,8 @@ static int vcpuset(uint32_t domid, const
> > > char*
> > > nr_vcpus, int check_host)
> > >          if (rc)
> > >              return 1;
> > >      }
> > > -    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus)) {
> > > +    rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
> > > +    if (rc) {
> > >          fprintf(stderr, "libxl_cpu_bitmap_alloc failed, rc:
> > > %d\n",
> > > rc);
> > >          return 1;
> > >      }
> > > 
> > Don't we also need to initialise rc to 0? It seems to me that it
> > may be
> > used uninitialised also inside of if(check_host)...
> 
> Looks like it, a separate issue though.
> 
The compiler is not spotting it again, though (just as a side note).

> Don't initialise rc to 0, add a suitable else though.
> 
Yeah, sure, I figured that out after having sent the mail. I'll send a
patch.

Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: [PATCH v2] xl: initialise rc before using it in vcpuset

[Ian Campbell]

On Wed, 2015-11-04 at 11:32 +0000, Wei Liu wrote:
> In 5b725e56 (xl: improve return and exit codes of vcpu related
> functions), the return value of libxl_cpu_bitmap_alloc was not stored in
> rc anymore. Yet the subsequent fprintf still used that.
> 
> Reinstate the original implementation, that is, to store return value of
> libxl_cpu_bitmap_alloc in rc before using rc.
> 
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>

Acked + applied.