[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <1321979579.18002.5.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
Date: Tue, 22 Nov 2011 17:32:59 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: Christoph Lameter <cl@...ux.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: WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413
Le mardi 22 novembre 2011 à 10:20 -0600, Christoph Lameter a écrit :
> Argh. The Redzoning (and the general object pad initialization) is outside
> of the slab_lock now. So I get wrong positives on those now. That
> is already in 3.1 as far as I know. To solve that we would have to cover a
> much wider area in the alloc and free with the slab lock.
>
> But I do not get the count mismatches that you saw. Maybe related to
> preemption. Will try that next.
Also I note the checks (redzoning and all features) that should be done
in kfree() are only done on slow path ???
f
...
stat(s, FREE_SLOWPATH);
if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
...
This is unfortunate...
I am considering adding a "quarantine" capability : each cpu will
maintain in its struct kmem_cache_cpu a FIFO list of "s->quarantine_max"
freed objects.
So it should be easier to track use after free bugs, setting
quarantine_max to a big value.
--
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
Powered by blists - more mailing lists