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From: Roland Dreier <rdreier@cisco.com>
To: Moni Shoua <monis@Voltaire.COM>
Cc: linux-rdma <linux-rdma@vger.kernel.org>,
	OpenFabrics General <general@lists.openfabrics.org>
Subject: [ofa-general] Re: [PATCH] IB/ipoib: Do not turn on carrier to a non active port
Date: Thu, 17 Sep 2009 08:50:18 -0700	[thread overview]
Message-ID: <adamy4td0zp.fsf@cisco.com> (raw)
In-Reply-To: <4AB20C6C.9090005@Voltaire.COM> (Moni Shoua's message of "Thu, 17 Sep 2009 13:16:12 +0300")

And by the way, this current patch has a deadlock I think:

 > @@ -724,6 +724,8 @@ int ipoib_ib_dev_down(struct net_device *dev, int flush)
 >  	ipoib_dbg(priv, "downing ib_dev\n");
 >  
 >  	clear_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
 > +	cancel_delayed_work(&priv->carrier_on_task);

ipoib_ib_dev_down() is called with rtnl held but carrier_on_task() does
rtn_lock().  So if carrier_on_task() is running but about to take the
rtnl when we try to do cancel_delayed_work() here, then it will wait
forever.

I think using lockdep on a new enough kernel (2.6.30 or maybe 2.6.31)
will report workqueue / timer vs. lock deadlocks.

 - R.

  parent reply	other threads:[~2009-09-17 15:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-17 10:16 [PATCH] IB/ipoib: Do not turn on carrier to a non active port Moni Shoua
     [not found] ` <4AB20C6C.9090005-hKgKHo2Ms0F+cjeuK/JdrQ@public.gmane.org>
2009-09-17 15:02   ` Roland Dreier
     [not found]     ` <ada4or1ehsj.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-21  9:28       ` Moni Shoua
2009-09-17 15:50 ` Roland Dreier [this message]
     [not found]   ` <adamy4td0zp.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-21  9:34     ` Moni Shoua
     [not found]       ` <4AB7488E.6090700-hKgKHo2Ms0F+cjeuK/JdrQ@public.gmane.org>
2009-09-21 15:45         ` Roland Dreier

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