From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Patrick McHardy <kaber@trash.net>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH] netfilter: fix race in conntrack between dump_table and destroy
Date: Sun, 09 Jan 2011 22:32:06 +0100 [thread overview]
Message-ID: <4D2A2956.8050505@netfilter.org> (raw)
In-Reply-To: <20101126135101.4e4b97cc@nehalam>
On 26/11/10 22:51, Stephen Hemminger wrote:
> The netlink interface to dump the connection tracking table has a race
> when entries are deleted at the same time. A customer reported a crash
> and the backtrace showed thatctnetlink_dump_table was running while a
> conntrack entry wasbeing destroyed.
> (see https://bugzilla.vyatta.com/show_bug.cgi?id=6402).
>
> According to RCU documentation, when using hlist_nulls the reader
> must handle the case of seeing a deleted entry and not proceed
> further down the linked list. The old code would continue
> which caused the scan to walk into the free list.
>
> This patch uses locking (rather than RCU) for this operation which
> is guaranteed safe, and no longer requires getting reference while
> doing dump operation.
I have put this in my tree:
http://1984.lsi.us.es/git/?p=net-2.6/.git;a=summary
I'll pass it to David for -stable inclusion.
prev parent reply other threads:[~2011-01-09 21:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-25 6:27 [RFC] netfilter: conntrack race between dump_table and destroy Stephen Hemminger
2010-11-25 6:34 ` Eric Dumazet
2010-11-25 7:00 ` Stephen Hemminger
2010-11-25 7:13 ` Eric Dumazet
2010-11-26 21:51 ` [PATCH] netfilter: fix race in conntrack " Stephen Hemminger
2010-11-27 6:32 ` Eric Dumazet
2010-11-30 17:28 ` Stephen Hemminger
2011-01-09 21:32 ` Pablo Neira Ayuso [this message]
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