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From: Florian Weimer <fweimer@redhat.com>
To: Ian Pilcher via Libc-help <libc-help@sourceware.org>
Cc: Ian Pilcher <arequipeno@gmail.com>
Subject: Re: Bug or not? printf allocates buffer & never frees it
References: <s2tebb$135j$1@ciao.gmane.io>
Date: Wed, 17 Mar 2021 18:45:57 +0100
In-Reply-To: <s2tebb$135j$1@ciao.gmane.io> (Ian Pilcher via Libc-help's
 message of "Wed, 17 Mar 2021 12:30:19 -0500")
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* Ian Pilcher via Libc-help:

> Fedora 33 with glibc-2.32-4.fc33.x86_64.
>
> Simple reproducer:
>
>  #include <mcheck.h>
>  #include <stdio.h>
>
>  int main(void)
>  {
> 	mtrace();
> 	printf("%d\n", 0);
> 	muntrace();
> 	return 0;
>  }
>
> Running with MALLOC_TRACE set shows:
>
>  Memory not freed:
>  -----------------
>             Address     Size     Caller
>  0x0000000000e1d690    0x400  at 0x7f19511d2934

> Is this considered a bug?

What happens if you remove the muntrace call?  I suspect you see this
leak because you are specifically telling glibc not to log the
deallocation.

Thanks,
Florian