Re: [RFC/PATCH] ignore memcmp() overreading in bsearch() callback

[Jeff King <peff@peff.net>]

On Mon, Jan 14, 2013 at 03:36:21PM -0800, Junio C Hamano wrote:

> It appears that memcmp() uses the usual "one word at a time"
> comparison and triggers valgrind in a callback of bsearch() used in
> the refname search.  I can easily trigger problems in any script
> with test_commit (e.g. "sh t0101-at-syntax.sh --valgrind -i -v")
> without this suppression.

Out of curiosity, what platform do you see this on? I can't reproduce on
glibc.

> diff --git a/t/valgrind/default.supp b/t/valgrind/default.supp
> index 0a6724f..032332f 100644
> --- a/t/valgrind/default.supp
> +++ b/t/valgrind/default.supp
> @@ -49,3 +49,11 @@
>  	Memcheck:Addr4
>  	fun:copy_ref
>  }
> +
> +{
> +	ignore-memcmp-reading-too-much-in-bsearch-callback
> +	Memcheck:Addr4
> +	fun:ref_entry_cmp_sslice
> +	fun:bsearch
> +	fun:search_ref_dir
> +}

Given that it is valgrind-clean on my platform, and reading the code I
don't see any problems, I think it probably is a false positive, and
this suppression makes sense.

-Peff