Re: [Bugme-new] [Bug 9564] New: Uninitialzed variable fieldscvt.h_margin and cvt.v_margin

[Andrew Morton]

On Fri, 14 Dec 2007 13:54:59 -0800 (PST)
bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=9564
> 
>            Summary: Uninitialzed variable fields cvt.h_margin and
>                     cvt.v_margin
>            Product: Drivers
>            Version: 2.5
>      KernelVersion: 2.6.23
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: Video(Other)
>         AssignedTo: drivers_video-other@xxxxxxxxxxxxxxxxxxxx
>         ReportedBy: marciobuss@xxxxxxxxx
> 
> 
> The errors can be found at drivers/video/fbcvt.c as follows:
> 
> (1) the test "if (margin)" at line 310 evaluates to false,
> (2) this makes the test "if (cvt.flags & FB_CVT_FLAG_MARGINS)" at line 352
>     to evaluate to false as well
> (3) now cvt.h_margin is uninitialized at line 359, 368, and 370, and
>     cvt.v_margin is uninitizalied at line 371.
> 
> In other words, both cvt.v_margin and cvt.h_margin are initialized conditinally
> but used unconditionally. This bug is a false positive only if the parameter
> "margins" at line 304 is never 0. However, this would make the test at line
> 310 unnecessary -- anyone looking at the code is miled into believing that
> 0 is a legal value for "margins". This means the code does require some change
> in my humble opinion.
> 

Could someone please take a look at this?
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