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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.os.linux.misc
Subject: Re: Joy of this, Joy of that
Date: Sat, 23 Nov 2024 21:45:19 -0000 (UTC)
Organization: A noiseless patient Spider
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On Sat, 23 Nov 2024 10:16:46 +0000, Richard Kettlewell wrote:

> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>>
>> One thing that helps is that free(3) is idempotent:
> 
> It is not. Freeing the same non-null pointer twice is a bug (and a
> common source of vulnerabilities).

That’s not what I meant by “idempotent”, and that particular case is easy 
to catch anyway, and glibc does so by default. See
<https://manpages.debian.org/3/mallopt.3.en.html>.