From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id ACC136B0035 for ; Sun, 14 Sep 2014 22:11:47 -0400 (EDT) Received: by mail-pa0-f54.google.com with SMTP id lj1so5424093pab.27 for ; Sun, 14 Sep 2014 19:11:47 -0700 (PDT) Received: from lgeamrelo01.lge.com (lgeamrelo01.lge.com. [156.147.1.125]) by mx.google.com with ESMTP id j5si20096234pdk.197.2014.09.14.19.11.45 for ; Sun, 14 Sep 2014 19:11:46 -0700 (PDT) Date: Mon, 15 Sep 2014 11:11:34 +0900 From: Joonsoo Kim Subject: Re: [PATCH] slab: implement kmalloc guard Message-ID: <20140915021133.GC2676@js1304-P5Q-DELUXE> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Mikulas Patocka Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Alasdair G. Kergon" , Mike Snitzer , Milan Broz , kkolasa@winsoft.pl, dm-devel@redhat.com On Thu, Sep 11, 2014 at 10:32:52PM -0400, Mikulas Patocka wrote: > > > On Mon, 8 Sep 2014, Christoph Lameter wrote: > > > On Mon, 8 Sep 2014, Mikulas Patocka wrote: > > > > > I don't know what you mean. If someone allocates 10000 objects with sizes > > > from 1 to 10000, you can't have 10000 slab caches - you can't have a slab > > > cache for each used size. Also - you can't create a slab cache in > > > interrupt context. > > > > Oh you can create them up front on bootup. And I think only the small > > sizes matter. Allocations >=8K are pushed to the page allocator anyways. > > Only for SLUB. For SLAB, large allocations are still use SLAB caches up to > 4M. But anyway - having 8K preallocated slab caches is too much. > > If you want to integrate this patch into the slab/slub subsystem, a better > solution would be to store the exact size requested with kmalloc along the > slab/slub object itself (before the preceding redzone). But it would > result in duplicating the work - you'd have to repeat the logic in this > patch three times - once for slab, once for slub and once for > kmalloc_large/kmalloc_large_node. > > I don't know if it would be better than this patch. Hello, Out of bound write could be detected by kernel address asanitizer(KASan). See following link. https://lkml.org/lkml/2014/9/10/441 Although this patch also looks good to me, I think that KASan is better than this, because it could detect out of bound write and has more features for debugging. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org