From: Jiri Bohac <jbohac@suse.cz>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Miller <davem@davemloft.net>,
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: Thu, 22 Apr 2010 17:49:08 +0200 [thread overview]
Message-ID: <20100422154908.GA31568@midget.suse.cz> (raw)
In-Reply-To: <20100422142506.GA15858@gondor.apana.org.au>
On Thu, Apr 22, 2010 at 10:25:06PM +0800, Herbert Xu wrote:
> This patch fixes this by using the DADFAILED bit to synchronise
> the two paths while holding the ifp lock. It relies on the fact
> that the TENTATIVE bit is always set during DAD, and that the
> DADFAILED bit is only set on failure.
But the addr_dad_failure()->...->ipv6_del_addr() path will
still race with any other path calling ipv6_del_addr() (e.g. a
manual address removal). Won't it?
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)?
--
Jiri Bohac <jbohac@suse.cz>
SUSE Labs, SUSE CZ
next prev parent reply other threads:[~2010-04-22 15:49 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 [this message]
2010-04-22 16:17 ` Stephen Hemminger
2010-04-23 1:54 ` David Miller
2010-04-23 2:10 ` Herbert Xu
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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