Messages in this thread | | | Date | Mon, 10 Jun 2002 07:22:35 +0200 | From | Kasper Dupont <> | Subject | Re: [CHECKER] 54 missing null pointer checks in 2.4.17 |
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Dawson Engler wrote: > > Enclosed are 54 potential errors where code gets a pointer from a > possibly-failing routine (kmalloc, etc) and dereferences it without > checking. Many follow the simple pattern of alloc-memset: > > dev->priv = kmalloc(sizeof(struct awc_private),GFP_KERNEL ); > memset(dev->priv,0,sizeof(struct awc_private)); > > If these kind of errors are useful, let me know --- there are *many* > others that I didn't inspect.
They surely look useful. Catching errors this way is better than having to experience every one on a production system before they are found. There are some false positives, but compared to the actual number of bugs found, that is not a problem.
> [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.
-- Kasper Dupont -- der bruger for meget tid på usenet. For sending spam use mailto:razor-report@daimi.au.dk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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