linux-kernel - Calling free_pages on part of the memory returned by get_free

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <480D032E.20204@freescale.com>
Date:	Mon, 21 Apr 2008 16:12:14 -0500
From:	Timur Tabi <timur@...escale.com>
To:	lkml <linux-kernel@...r.kernel.org>
Subject: Calling free_pages on part of the memory returned by get_free_pages?

According to LDD3, if I call get_free_pages() to allocate X bytes, I have to
free all of those pages with free_pages().  The VM internals are a little bit
over my head, but I looked at the code and I didn't see why that is a requirement.

For example, let's say I want to allocated 6MB of physically-contiguous memory.
 If I call x = get_free_pages(11) to get 8MB.  What happens if I then do
"free_pages(x + 6 * 1024 * 1024, 9)"?

I remember doing this on the 2.4 kernel, and it never gave me any problems.

-- 
Timur Tabi
Linux kernel developer at Freescale
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/