Comment 39 for bug 852760

(In reply to Miroslav Lichvar from comment #18)
> I don't see how is this a libidn problem, the code just calls strlen() on a
> properly allocated buffer. Either it's a bug in valgrind that it reports
> false positives or gcc generates bad code.

As stated in comment #16 gcc generates code that valgrind can only "prove" correct when using --partial-loads-ok=yes. The code does a multi-byte loads from addresses which are partially valid and partially invalid. See that comment or the valgrind manual for more explanation.