Re: [PATCH 0/6] improve list_sort test

[Artem Bityutskiy]

On Sat, 2010-08-07 at 11:10 +0300, Artem Bityutskiy wrote:
> Hi,
> 
> while hunting a non-existing bug in 'list_sort()', I've improved the
> 'list_sort_test()' function which tests the 'list_sort()' library call. Although
> at the end I found a bug in my code, but not in 'list_sort()', I think my
> clean-ups and improvements are worth merging because they make the test function
> better.

Actually, your 'list_sort()' version does have a problem. I found out
that it calls 'cmp(priv, a, b)' with 'a = b' sometimes, and in these
cases 'a' and 'b' can point to something which is not a valid element of
the original list. Probably a senitel or something like that.

It is easy to work around this by adding:

if (a == b)
	return 0;

in the 'cmp()' function, but this is nevertheless a bug (not too bad,
though) and should be fixed. Also, the fact that 'cmp()' is called with
'a==b' sometimes should be documented.

I'm CC-ing 2 other users of 'list_sort()' for head-ups (xfs, drm).

I've fixed assertions in UBIFS using the following patch:

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