Re: [2.6.19 patch] drivers/block/aoe/aoedev.c: fix NULL dereference

From: Adrian Bunk
Date: Wed Nov 01 2006 - 13:39:49 EST


On Wed, Nov 01, 2006 at 11:36:28AM -0500, Ed L. Cashin wrote:
> On Wed, Nov 01, 2006 at 01:40:25AM +0100, Adrian Bunk wrote:
> > This patch fixes a NULL dereference introduced by
> > commit e407a7f6cd143b3ab4eb3d7e1cf882e96b710eb5:
> >
> > This quite unusual error handling through a switch introduces NULL
> > dereferences if exactly one of the two k{c,z}alloc's failed.
>
> Hmm. If exactly one of the two fails, then the value of the switch
> conditional is 1 (well, certainly not zero). It will jump over the
> zero case, and there's a return in the default case, so I'm having
> trouble seeing the danger.
>
> What exactly is Coverity saying? That would be interesting to know.

The Coverity checker was wrong in this case, and I didn't spot it when
checking since the code is really confusing.

> Ed L Cashin <ecashin@xxxxxxxxxx>

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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