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

[Kyle Moffett <mrmacman_g4@mac.com>]

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