From: Jeff King <peff@peff.net>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [PATCH 2/6] commit: copy saved getenv() result
Date: Tue, 15 Jan 2019 14:17:14 -0500 [thread overview]
Message-ID: <20190115191714.GD4886@sigill.intra.peff.net> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.1901151502130.41@tvgsbejvaqbjf.bet>
On Tue, Jan 15, 2019 at 03:05:50PM +0100, Johannes Schindelin wrote:
> > But certainly it would not be the first such instance in our code base.
>
> Just because a lot of our code has grown historically does not mean that
> we need to add code that shares the same shortcomings. FREE_AND_NULL() was
> not available for a long time, after all, so it is understandable that we
> did not use it back then. But it is available now, so we no longer have an
> excuse to add less defensive code.
Fair enough. I am happy to start using FREE_AND_NULL() consistently if
nobody things it's too opaque (or that it creates confusion that we
somehow expect to look at the variable again and need it to be NULL). I
think the compiler should generally be able to optimize out the NULL
assignment in most cases anyway.
> > In theory a static analyzer should easily be able to figure out such a
> > problem, too, so maybe it is not worth being defensive about.
>
> How often do you run a static analyzer?
Stefan was routinely running coverity, though I haven't seen results in
a while. I think we should make sure that continues, as it did turn up
some useful results (and a lot of cruft, too, but on the whole I have
found it useful).
I also count gcc as a static analyzer, since it can and does point out
many simple problems. I don't know that it can point out an obvious
user-after-free like this, though.
That said....
> My point being: if we can prevent future mistakes easily, and it does not
> add too much code churn, why not just do it. No need to rely on fancy
> stuff that might not even be available on your preferred platform.
Yeah, I do agree (which is why I included it in the patch ;) ).
-Peff
next prev parent reply other threads:[~2019-01-15 19:17 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 22:14 [PATCH 0/6] getenv() timing fixes Jeff King
2019-01-11 22:15 ` [PATCH 1/6] get_super_prefix(): copy getenv() result Jeff King
2019-01-12 3:02 ` Junio C Hamano
2019-01-11 22:15 ` [PATCH 2/6] commit: copy saved " Jeff King
2019-01-12 3:07 ` Junio C Hamano
2019-01-12 10:26 ` Jeff King
2019-01-15 14:05 ` Johannes Schindelin
2019-01-15 19:17 ` Jeff King [this message]
2019-01-15 19:25 ` Stefan Beller
2019-01-15 19:32 ` Jeff King
2019-01-16 14:06 ` Johannes Schindelin
2019-01-11 22:15 ` [PATCH 3/6] config: make a copy of $GIT_CONFIG string Jeff King
2019-01-11 22:16 ` [PATCH 4/6] init: make a copy of $GIT_DIR string Jeff King
2019-01-12 3:08 ` Junio C Hamano
2019-01-11 22:16 ` [PATCH 5/6] merge-recursive: copy $GITHEAD strings Jeff King
2019-01-12 3:10 ` Junio C Hamano
2019-01-11 22:17 ` [PATCH 6/6] builtin_diff(): read $GIT_DIFF_OPTS closer to use Jeff King
2019-01-12 11:31 ` [PATCH 0/6] getenv() timing fixes Ævar Arnfjörð Bjarmason
2019-01-12 18:51 ` Stefan Beller
2019-01-15 19:13 ` Jeff King
2019-01-15 19:32 ` Junio C Hamano
2019-01-15 19:38 ` Stefan Beller
2019-01-15 19:41 ` Jeff King
2019-01-15 19:47 ` Jeff King
2019-01-15 20:49 ` Junio C Hamano
2019-01-15 19:12 ` Jeff King
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