linux-kernel - bootmem: Double freeing a PFN on nodes spanning other nodes

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Sat, 17 May 2008 00:30:55 +0200
From:	Johannes Weiner <hannes@...urebad.de>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
CC:	Linux MM Mailing List <linux-mm@...ck.org>
Subject: bootmem: Double freeing a PFN on nodes spanning other nodes

Hi,

When memory nodes overlap each other, the bootmem allocator is not aware
of this and might pass the same page twice to __free_pages_bootmem().

As I traced the code, this should result in bad_page() calls on every
boot but noone has yet reported something like this and I am wondering
why.

__free_pages_bootmem() boils down to either free_hot_cold_page() or
__free_one_page().  Either path should lead to setting the page private
or buddy:

free_hot_cold_page() sets ->private to the page block's migratetype (and
sets PG_private).

__free_one_page sets ->private to the page's order (and sets PG_private
and PG_buddy).

If a page is passed in twice, free_pages_check() should now warn (via
bad_page()) on the flags set above.

Am I missing something?  Thanks in advance.

	Hannes
--
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/