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From: Richard Kettlewell <invalid@invalid.invalid>
Newsgroups: comp.os.linux.misc
Subject: Re: Joy of this, Joy of that
Date: Sun, 24 Nov 2024 12:46:46 +0000
Organization: terraraq NNTP server
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Lawrence D'Oliveiro <ldo@nz.invalid> writes:
> 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”,

It’s what everyone else means by it.

> 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>.

Glibc’s double free detection is heuristic, not 100% reliable.

-- 
https://www.greenend.org.uk/rjk/