Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933337Ab2FHFQs (ORCPT ); Fri, 8 Jun 2012 01:16:48 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43276 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761330Ab2FHFH0 (ORCPT ); Fri, 8 Jun 2012 01:07:26 -0400 Message-Id: <20120608041845.680203839@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 08 Jun 2012 05:19:16 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Joonsoo Kim , Christoph Lameter , Pekka Enberg Subject: [ 36/82] slub: fix a memory leak in get_partial_node() In-Reply-To: <20120608041840.861504477@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2946 Lines: 89 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joonsoo Kim commit 02d7633fa567be7bf55a993b79d2a31b95ce2227 upstream. In the case which is below, 1. acquire slab for cpu partial list 2. free object to it by remote cpu 3. page->freelist = t then memory leak is occurred. Change acquire_slab() not to zap freelist when it works for cpu partial list. I think it is a sufficient solution for fixing a memory leak. Below is output of 'slabinfo -r kmalloc-256' when './perf stat -r 30 hackbench 50 process 4000 > /dev/null' is done. ***Vanilla*** Sizes (bytes) Slabs Debug Memory ------------------------------------------------------------------------ Object : 256 Total : 468 Sanity Checks : Off Total: 3833856 SlabObj: 256 Full : 111 Redzoning : Off Used : 2004992 SlabSiz: 8192 Partial: 302 Poisoning : Off Loss : 1828864 Loss : 0 CpuSlab: 55 Tracking : Off Lalig: 0 Align : 8 Objects: 32 Tracing : Off Lpadd: 0 ***Patched*** Sizes (bytes) Slabs Debug Memory ------------------------------------------------------------------------ Object : 256 Total : 300 Sanity Checks : Off Total: 2457600 SlabObj: 256 Full : 204 Redzoning : Off Used : 2348800 SlabSiz: 8192 Partial: 33 Poisoning : Off Loss : 108800 Loss : 0 CpuSlab: 63 Tracking : Off Lalig: 0 Align : 8 Objects: 32 Tracing : Off Lpadd: 0 Total and loss number is the impact of this patch. Acked-by: Christoph Lameter Signed-off-by: Joonsoo Kim Signed-off-by: Pekka Enberg Signed-off-by: Ben Hutchings --- mm/slub.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/mm/slub.c +++ b/mm/slub.c @@ -1506,15 +1506,19 @@ freelist = page->freelist; counters = page->counters; new.counters = counters; - if (mode) + if (mode) { new.inuse = page->objects; + new.freelist = NULL; + } else { + new.freelist = freelist; + } VM_BUG_ON(new.frozen); new.frozen = 1; } while (!__cmpxchg_double_slab(s, page, freelist, counters, - NULL, new.counters, + new.freelist, new.counters, "lock and freeze")); remove_partial(n, page); @@ -1556,7 +1560,6 @@ object = t; available = page->objects - page->inuse; } else { - page->freelist = t; available = put_cpu_partial(s, page, 0); } if (kmem_cache_debug(s) || available > s->cpu_partial / 2) -- 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/