netdev - Re: slub: Lockout validation scans during freeing of object

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.1111221144580.28197@router.home>
Date:	Tue, 22 Nov 2011 11:59:22 -0600 (CST)
From:	Christoph Lameter <cl@...ux.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
cc:	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Christian Kujau <lists@...dbynature.de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	"Alex,Shi" <alex.shi@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	Pekka Enberg <penberg@...nel.org>,
	Matt Mackall <mpm@...enic.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Tejun Heo <tj@...nel.org>
Subject: Re: slub: Lockout validation scans during freeing of object

On Tue, 22 Nov 2011, Eric Dumazet wrote:

> This seems better, but I still have some warnings :
>
> [  162.117574] SLUB: selinux_inode_security 136 slabs counted but counter=137
> [  179.879907] SLUB: task_xstate 1 slabs counted but counter=2

This is the total # of slabs that mismatches. Some slabs are not on the
partial list and are neither on the full list since they are currently
on the per cpu partial lists. Thats an accounting issue introduced in 3.2
with the per cpu pages. Need to find some way to count the per cpu partial
pages correctly. Could just force the per cpu pages to be empty?


Subject: Switch per cpu partial page support off for debugging

Otherwise we have accounting issues.

Signed-off-by: Christoph Lameter <cl@...ux.com>


---
 mm/slub.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2011-11-22 11:57:21.000000000 -0600
+++ linux-2.6/mm/slub.c	2011-11-22 11:57:55.000000000 -0600
@@ -3027,7 +3027,9 @@ static int kmem_cache_open(struct kmem_c
 	 *    per node list when we run out of per cpu objects. We only fetch 50%
 	 *    to keep some capacity around for frees.
 	 */
-	if (s->size >= PAGE_SIZE)
+	if (kmem_cache_debug(s))
+		s->cpu_partial = 0;
+	else if (s->size >= PAGE_SIZE)
 		s->cpu_partial = 2;
 	else if (s->size >= 1024)
 		s->cpu_partial = 6;
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html