Re: [CHECKER] 54 missing null pointer checks in 2.4.17

From: Dawson Engler (engler@csl.Stanford.EDU)
Date: Mon Jun 10 2002 - 00:56:56 EST


> > [BUG] (synonums aren't working)
> > /u2/engler/mc/oses/linux/2.4.17/drivers/net/eexpress.c:1088:eexp_hw_probe:
> > ERROR:NULL:1083:1088:Using ptr "lp" illegally! set by 'kmalloc':1083
> > [COUNTER=kmalloc:1083] [fit=1] [fit_fn=5] [fn_ex=0] [fn_counter=1]
> > [ex=1399] [counter=26] [z = 5.50002098543802] [fn-z = -4.35889894354067]
> > }
> >
> > buswidth = !((setupval & 0x400) >> 10);
> > }
> >
> > Start --->
> > dev->priv = lp = kmalloc(sizeof(struct net_local), GFP_KERNEL);
> > if (!dev->priv)
> > return -ENOMEM;
> >
> > memset(dev->priv, 0, sizeof(struct net_local));
> > Error --->
> > spin_lock_init(&lp->lock);
>
> This one isn't a bug. The pointer to allocated memory is stored in two
> variables. Only one of them is verified against NULL, that is enough.

Yuck. Sorry about that --- I mislabeled the message. It's a BUG,
but in our system rather than in 2.4.17. Bug finding still tends
to be unfortunately symetrical...
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