Messages in this thread | | | Date | Fri, 1 Jun 2007 21:45:15 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: SLUB: Return ZERO_SIZE_PTR for kmalloc(0) |
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On Fri, 1 Jun 2007, Andrew Morton wrote:
> They are different instances which happen to have the same length (zero).
I guess one could use the slab allocators as a type of reservation ticket generator with zero sized objects. Hmmm.... But is that really a useful thing to do?
> But the code will incorrectly decide that they are the same instance. It > might cause refcounting or accounting errors, for example. I don't know - the > kernel's a big place.
That would have to occur with objects that are repeatedly allocated and then linked toghether etc. Linking typicallty requires a listhead so its typically difficult to do zero length objects. > I agree the risk is low, but if something _does_ blow up, it will do so subtly.
The cases that we have seen so far are due to array allocations of N elements where N == 0 leads to the creation of a zero sized object. The objects of the array are not zero sized it is just that zero of them are allocated. - 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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