Re: fs/block_dev.c:953: warning: 'found' might be used uninitialized in this function

[Kyle Moffett]

On Mar 28, 2007, at 16:14:54, Andrew Morton wrote:
> On Wed, 28 Mar 2007 19:23:32 +0200 (CEST)
> Jiri Kosina <jikos@xxxxxxxx> 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.

Cheers,
Kyle Moffett

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