Re: [PATCH] Add MALLOC_CHECK_ and MALLOC_PERTURB_ libc env to the test suite for detecting heap corruption

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 13, 2012, 17:46 UTC
Message-ID: <7vvcfh95o9.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CA+EOSBmjwUA_Sogo5ZixnAE5_6C97wjEOzO6PnDgjw_BYzVz-w@mail.gmail.com>

Elia Pinto <gitter.spiros@gmail.com> writes:

Show 8 quoted lines

> 2012/9/12 Junio C Hamano <gitster@pobox.com>:
>>
>> Interesting, but it bothers me to make it enabled unconditionally.
>> At least, this shouldn't be enabled under GIT_TEST_OPTS=--valgrind, no?
> Sorry for the late response and thanks.
>
> No, setting MALLOC_CHECK don't require
> valgrind ...

You never said anything like that, and I didn't question it.

> and it considered a best QA to have the test suite with it
> defined always. If the test suite fail with MALLOC_CHECK, well, there
> is some problem, no ?

I never said using MALLOC_CHECK_ is a bad idea.

Let me ask the same question in a different way, as I seem to have failed in the previous message.

If you are using valgrind to run tests, is it sane to also enable MALLOC_CHECK? If you were testing "cat", would it make sense to do:

	$ MALLOC_CHECK_=3 valgrind cat README

Because we are not interested in testing how valgrind (not cat) uses malloc, we may be better off running

	$ valgrind cat README

without MALLOC_CHECK_; it will reduce the risk of MALLOC_CHECK_ potentially disturbing what we really want to check (i.e. cat) by triggering for something whose problems we are not trying to see (i.e. valgrind), no?

That was my question.