From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH] slub: fix slab_pad_check() Date: Thu, 03 Sep 2009 16:08:06 +0200 Message-ID: <4A9FCDC6.3060003@gmail.com> References: <4A87CE60.4020506@gmail.com> <4A896324.3040104@trash.net> <4A9EEF07.5070800@gmail.com> <4A9F1620.2080105@gmail.com> <84144f020909022331x2b275aa5n428f88670e0ae8bc@mail.gmail.com> <4A9F7283.1090306@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Pekka Enberg , Zdenek Kabelac , Patrick McHardy , Robin Holt , Linux Kernel Mailing List , Jesper Dangaard Brouer , Linux Netdev List , Netfilter Developers , paulmck@linux.vnet.ibm.com To: Christoph Lameter Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Christoph Lameter a =E9crit : > On Thu, 3 Sep 2009, Eric Dumazet wrote: >=20 >> on a SLAB_DESTROY_BY_RCU cache, there is no need to try to optimize = this >> rcu_barrier() call, unless we want superfast reboot/halt sequences..= =2E >=20 > I stilll think that the action to quiesce rcu is something that the c= aller > of kmem_cache_destroy must take care of. Do you mean : if (kmem_cache_shrink(s) =3D=3D 0) { rcu_barrier(); kmem_cache_destroy_no_rcu_barrier(s); } else { kmem_cache_destroy_with_rcu_barrier_because_SLAB_DESTROY_BY_RCU_cache(= s); } What would be the point ? >=20 > Could you split this into two patches: One that addresses the poison = and > another that deals with rcu? >=20 Sure, here is the poison thing [PATCH] slub: fix slab_pad_check() When SLAB_POISON is used and slab_pad_check() finds an overwrite of the slab padding, we call restore_bytes() on the whole slab, not only on the padding. Reported-by: Zdenek Kabelac Signed-off-by: Eric Dumazet --- diff --git a/mm/slub.c b/mm/slub.c index b9f1491..0ac839f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -646,7 +646,7 @@ static int slab_pad_check(struct kmem_cache *s, str= uct page *page) slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); print_section("Padding", end - remainder, remainder); =20 - restore_bytes(s, "slab padding", POISON_INUSE, start, end); + restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end); return 0; } =20