From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: dormando <dormando@rydia.net>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: Multitude of dst obsolescense race conditions
Date: Fri, 6 Jun 2014 15:17:49 -0700 [thread overview]
Message-ID: <20140606221749.GX4581@linux.vnet.ibm.com> (raw)
In-Reply-To: <1402081030.3645.312.camel@edumazet-glaptop2.roam.corp.google.com>
On Fri, Jun 06, 2014 at 11:57:10AM -0700, Eric Dumazet wrote:
> On Fri, 2014-06-06 at 11:12 -0700, Paul E. McKenney wrote:
>
> > It is probably just be me getting lost in the code, but I am not seeing
> > a synchronize_rcu(), call_rcu(), or synchronize_net() anywhere in
> > dst_release() or the things that it calls. If there really isn't such
> > a call, then I don't see how the above code is safe in the case where
> > __sk_dst_set() is invoked on one CPU just after sk_dst_get() executes
> > the rcu_dereference() on some other CPU.
>
> Well, this part is fine, dst_release() do not free dst that are
> potentially stored in sk_dst_cache
>
> Only the refcount is decremented.
>
> The bug is elsewhere, we had another thread raising this issue on netdev
> this morning.
>
> I am cooking a patch to clear the mess.
Ah, thank you, sorry for the noise!
Thanx, Paul
next prev parent reply other threads:[~2014-06-06 22:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-14 9:57 Multitude of dst obsolescense race conditions dormando
2014-05-14 11:40 ` Eric Dumazet
2014-05-14 17:59 ` dormando
2014-06-06 18:12 ` Paul E. McKenney
2014-06-06 18:57 ` Eric Dumazet
2014-06-06 22:17 ` Paul E. McKenney [this message]
2014-05-14 13:35 ` Hannes Frederic Sowa
2014-05-14 18:01 ` dormando
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