On Tue, 2016-02-02 at 12:37 +0000, Wei Liu wrote:
> On Tue, Feb 02, 2016 at 12:33:20PM +0100, Roger Pau Monne wrote:
> > From: Roger Pau Monne <[email protected]>
> >
> > Due to the HVMlite changes there's a chance that the value in rc is
> > checked
> > without being initialised. Fix this by initialising it to 0.
> >
> > Signed-off-by: Roger Pau Monné <[email protected]>
> > Reported-by: Olaf Hering <[email protected]>
>
> Acked-by: Wei Liu <[email protected]>
This is CID 1351229, I think?
** CID 1351229: Uninitialized variables (UNINIT)
> /tools/libxc/xc_dom_x86.c: 1443 in meminit_hvm()
>
>
> ________________________________________________________________________________________________________
> *** CID 1351229: Uninitialized variables (UNINIT)
> /tools/libxc/xc_dom_x86.c: 1443 in meminit_hvm()
> 1437 cur_pages = 0xc0;
> 1438 stat_normal_pages += 0xc0;
> 1439 }
> 1440 else
> 1441 cur_pages = vmemranges[vmemid].start >> PAGE_SHIFT;
> 1442
> >>> CID 1351229: Uninitialized variables (UNINIT)
> >>> Using uninitialized value "rc".
> 1443 while ( (rc == 0) && (end_pages > cur_pages) )
> 1444 {
> 1445 /* Clip count to maximum 1GB extent. */
> 1446 unsigned long count = end_pages - cur_pages;
> 1447 unsigned long max_pages = SUPERPAGE_1GB_NR_PFNS;
> 1448
Note that this while loop ends with:
if ( rc != 0 )
break;
and there are no continue statements.
Therefore I wonder if we would be better off removing the rc == 0 part of
the loop condition?
The issue with this patch is the usual one that it will hide other
unintentional uses of rc before it is set to a good value.
This issue was exposed by a prior "rc = xc_domain_populate_physmap_exact"
becoming conditional on device_model. What is also concerning is the lack
of error checking on that call -- is it really ok to just barrel on under
these circumstance?
Ian.
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