From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752070Ab0CXVZ4 (ORCPT ); Wed, 24 Mar 2010 17:25:56 -0400 Received: from nlpi157.sbcis.sbc.com ([207.115.36.171]:38126 "EHLO nlpi157.prodigy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750956Ab0CXVZx (ORCPT ); Wed, 24 Mar 2010 17:25:53 -0400 Date: Wed, 24 Mar 2010 16:25:47 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: Eric Dumazet cc: Pekka J Enberg , linux-kernel Subject: Re: [PATCH] slub: Potential stack overflow In-Reply-To: Message-ID: References: <1269430856.3213.27.camel@edumazet-laptop> <1269458528.2849.2.camel@edumazet-laptop> <1269464591.2849.15.camel@edumazet-laptop> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Here is a patch for the second case. I think its better since it results in an error display and it avoids the alloc for each slab. Add this piece to your patch? V1->V2 Fix missing kfree Signed-off-by: Christoph Lameter --- mm/slub.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) Index: linux-2.6/mm/slub.c =================================================================== --- linux-2.6.orig/mm/slub.c 2010-03-24 16:23:19.000000000 -0500 +++ linux-2.6/mm/slub.c 2010-03-24 16:24:21.000000000 -0500 @@ -3648,10 +3648,10 @@ static int add_location(struct loc_track } static void process_slab(struct loc_track *t, struct kmem_cache *s, - struct page *page, enum track_item alloc) + struct page *page, enum track_item alloc, + unsigned long *map) { void *addr = page_address(page); - DECLARE_BITMAP(map, page->objects); void *p; bitmap_zero(map, page->objects); @@ -3670,8 +3670,10 @@ static int list_locations(struct kmem_ca unsigned long i; struct loc_track t = { 0, 0, NULL }; int node; + unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) * + sizeof(unsigned long), GFP_KERNEL); - if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), + if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), GFP_TEMPORARY)) return sprintf(buf, "Out of memory\n"); @@ -3688,11 +3690,12 @@ static int list_locations(struct kmem_ca spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, lru) - process_slab(&t, s, page, alloc); + process_slab(&t, s, page, alloc, map); list_for_each_entry(page, &n->full, lru) - process_slab(&t, s, page, alloc); + process_slab(&t, s, page, alloc, map); spin_unlock_irqrestore(&n->list_lock, flags); } + kfree(map); for (i = 0; i < t.count; i++) { struct location *l = &t.loc[i];