Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754669Ab2B2IeE (ORCPT ); Wed, 29 Feb 2012 03:34:04 -0500 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:62583 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751268Ab2B2IeD (ORCPT ); Wed, 29 Feb 2012 03:34:03 -0500 X-AuditID: 9c930197-b7ccaae000003d69-d0-4f4de2f77cd3 From: Namhyung Kim To: Christoph Lameter , Pekka Enberg , Matt Mackall Cc: Namhyung Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH -next] slub: set PG_slab on all of slab pages Date: Wed, 29 Feb 2012 17:54:34 +0900 Message-Id: <1330505674-31610-1-git-send-email-namhyung.kim@lge.com> X-Mailer: git-send-email 1.7.9 X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2191 Lines: 70 Unlike SLAB, SLUB doesn't set PG_slab on tail pages, so if a user would call free_pages() incorrectly on a object in a tail page, she will get confused with the undefined result. Setting the flag would help her by emitting a warning on bad_page() in such a case. Reported-by: Sangseok Lee Signed-off-by: Namhyung Kim --- mm/slub.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 33bab2aca882..575baacbec9b 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1287,6 +1287,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) struct page *page; struct kmem_cache_order_objects oo = s->oo; gfp_t alloc_gfp; + int i; flags &= gfp_allowed_mask; @@ -1320,6 +1321,9 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) if (!page) return NULL; + for (i = 0; i < 1 << oo_order(oo); i++) + __SetPageSlab(page + i); + if (kmemcheck_enabled && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) { int pages = 1 << oo_order(oo); @@ -1369,7 +1373,6 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) inc_slabs_node(s, page_to_nid(page), page->objects); page->slab = s; - page->flags |= 1 << PG_slab; start = page_address(page); @@ -1396,6 +1399,7 @@ static void __free_slab(struct kmem_cache *s, struct page *page) { int order = compound_order(page); int pages = 1 << order; + int i; if (kmem_cache_debug(s)) { void *p; @@ -1413,7 +1417,11 @@ static void __free_slab(struct kmem_cache *s, struct page *page) NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, -pages); - __ClearPageSlab(page); + for (i = 0; i < pages; i++) { + BUG_ON(!PageSlab(page + i)); + __ClearPageSlab(page + i); + } + reset_page_mapcount(page); if (current->reclaim_state) current->reclaim_state->reclaimed_slab += pages; -- 1.7.9 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/