From d32ddd8f20e7d7a49c45c337c2079be03c77dc41 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Thu, 15 Nov 2007 12:32:04 +0100 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar Acked-by: Matt Mackall Signed-off-by: Linus Torvalds --- mm/slob.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/slob.c b/mm/slob.c index 5bc2ceb692ec..08a9bd91a1aa 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -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 * search time by starting our next search here. (see * 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); break; }