From: Herbert Xu <herbert@gondor.apana.org.au>
To: David Miller <davem@davemloft.net>
Cc: jbohac@suse.cz, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org,
shemminger@vyatta.com
Subject: Re: IPv6: race condition in __ipv6_ifa_notify() and dst_free() ?
Date: Fri, 23 Apr 2010 10:10:00 +0800 [thread overview]
Message-ID: <20100423021000.GA21777@gondor.apana.org.au> (raw)
In-Reply-To: <20100422.185400.71096585.davem@davemloft.net>
On Thu, Apr 22, 2010 at 06:54:00PM -0700, David Miller wrote:
> From: Jiri Bohac <jbohac@suse.cz>
> Date: Thu, 22 Apr 2010 17:49:08 +0200
>
> > I still don't see why __ipv6_ifa_notify() needs to call
> > dst_free(). Shouldn't that be dst_release() instead, to drop the
> > reference obtained by dst_hold(&ifp->rt->u.dst)?
>
> It likely wants to do both.
Actually I don't think the problem is in __ipv6_ifa_notify. The
fact is none of this stuff is meant to be idempotent. So it's
up to the entity that is requesting the deletion to make sure that
a single object is not deleted more than once.
Yes the original symptom was in __ipv6_ifa_notify, but it is
merely pointing out that we have a problem further up.
My patch is indeed not sufficient as Jiri pointed out, because
I didn't deal with the case of an administrative deletion of
autmatically generated IPv6 addresses.
I will post an updated patch later today to deal with that.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2010-04-23 2:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-20 17:44 IPv6: race condition in __ipv6_ifa_notify() and dst_free() ? Jiri Bohac
2010-04-20 17:57 ` Eric Dumazet
2010-04-20 20:49 ` Jiri Bohac
2010-04-20 20:57 ` Eric Dumazet
2010-04-20 21:16 ` Stephen Hemminger
2010-04-20 21:35 ` Jiri Bohac
2010-04-21 21:34 ` Jiri Bohac
2010-04-22 2:32 ` Herbert Xu
2010-04-22 7:43 ` David Miller
2010-04-22 14:25 ` Herbert Xu
2010-04-22 15:49 ` Jiri Bohac
2010-04-22 16:17 ` Stephen Hemminger
2010-04-23 1:54 ` David Miller
2010-04-23 2:10 ` Herbert Xu [this message]
2010-04-23 15:05 ` Herbert Xu
2010-05-18 11:02 ` [0/4] Fix addrconf race conditions Herbert Xu
2010-05-18 11:04 ` [PATCH 1/4] ipv6: Replace inet6_ifaddr->dead with state Herbert Xu
2010-05-18 17:23 ` Stephen Hemminger
2010-05-18 22:27 ` David Miller
2010-05-18 11:04 ` [PATCH 2/4] ipv6: Use state_lock to protect ifa state Herbert Xu
2010-05-18 11:04 ` [PATCH 3/4] ipv6: Use POSTDAD state Herbert Xu
2010-05-18 11:04 ` [PATCH 4/4] ipv6: Never schedule DAD timer on dead address Herbert Xu
2010-05-18 17:25 ` [0/4] Fix addrconf race conditions Stephen Hemminger
2010-05-18 22:27 ` David Miller
2010-05-18 22:35 ` Herbert Xu
2010-04-27 15:50 ` IPv6: race condition in __ipv6_ifa_notify() and dst_free() ? Jiri Bohac
2010-04-27 15:55 ` Herbert Xu
2010-05-09 6:48 ` Herbert Xu
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