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SubjectRe: [PATCH 0/6] improve list_sort test
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On Sun, 2010-08-08 at 12:31 -0700, Don Mullis wrote:
> Yes, invalid 'a' or 'b' pointers would be a bug. If providing a test
> case is hard, can you say what segment is pointed to? Into the stack?
> Into address ranges normal for elements, but not now on the list? Is
> there a pattern to the values returned? Is it perhaps always the
> first or last callback from a particular call to list_sort()?

You've correctly identified in the the other mail that 'a' and 'b'
sometimes point to the list head. I've just checked this.

> That sometimes a==b is, on the other hand, by design:
>
> /*
> * In worst cases this loop may run many iterations.
> * Continue callbacks to the client even though no
> * element comparison is needed, so the client's cmp()
> * routine can invoke cond_resched() periodically.
> */
> (*cmp)(priv, tail, tail);
>
> Adding a sentence to the function header comment reminding callers
> that they need to be able to handle a==b seems like a good idea.

OK, I'll add it.

--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

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