Commit d32ddd8f authored Nov 15, 2007 by Nick Piggin Committed by Linus Torvalds Nov 15, 2007

slob: fix memory corruption

Previously, it would be possible for prev->next to point to
&free_slob_pages, and thus we would try to move a list onto itself, and
bad things would happen.

It seems a bit hairy to be doing list operations with the list marker as
an entry, rather than a head, but...

this resolves the following crash:

  http://bugzilla.kernel.org/show_bug.cgi?id=9379



Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a3474224

mm/slob.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -321,7 +321,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
	/* Improve fragment distribution and reduce our average		/* Improve fragment distribution and reduce our average
	* search time by starting our next search here. (see		* search time by starting our next search here. (see
	* Knuth vol 1, sec 2.5, pg 449) */		* Knuth vol 1, sec 2.5, pg 449) */
	if (free_slob_pages.next != prev->next)		if (prev != free_slob_pages.prev &&
			free_slob_pages.next != prev->next)
	list_move_tail(&free_slob_pages, prev->next);		list_move_tail(&free_slob_pages, prev->next);
	break;		break;
	}		}