On Thu, Mar 29, 2007 at 11:16:39PM -0400, Kyle Moffett wrote:
> On Mar 28, 2007, at 16:14:54, Andrew Morton wrote:
> >On Wed, 28 Mar 2007 19:23:32 +0200 (CEST)
> >Jiri Kosina <[EMAIL PROTECTED]> wrote:
> >
> >>blockdev: bd_claim_by_kobject() could check value of unititalized
> >>pointer
> >>
> >>Fixes this warning:
> >>
> >>fs/block_dev.c: In function `bd_claim_by_kobject':
> >>fs/block_dev.c:953: warning: 'found' might be used uninitialized
> >>in this function
> >>
> >>struct bd_holder *found is initialized only when bd_claim()
> >>returns zero. If it returns nonzero, ptr stays uninitialized.
> >>Later the value of the pointer is checked.
> >
> >that generates extra code and people get upset.
> >
> >One approach which we could ue in here is
> >
> > struct bd_holder *found = found; /* Suppress bogus gcc warning */
>
> Well, that would be correct except the warning is an actual kernel
> bug. Read Jiri's message (which you also quoted):
> >struct bd_holder *found is initialized only when bd_claim() returns
> >zero. If it returns nonzero, ptr stays uninitialized. Later the
> >value of the pointer is checked.
>
> So in this case it has to be initialized to NULL or there's a
> potential BUG() lurking.
No, the code is correct and it's impossible that the variable ever gets
read uninitialized.
And BTW, i386 gcc 4.1 doesn't give me a warning for this.
Toralf, which gcc version and architecture did you see this with?
> Cheers,
> Kyle Moffett
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
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