From mboxrd@z Thu Jan  1 00:00:00 1970
From: Patrick McHardy <kaber@trash.net>
Subject: Re: [Patch net 2/2] net_sched: always call ->destroy when ->init()
 fails
Date: Sat, 25 Oct 2014 01:44:04 +0100
Message-ID: <20141025004403.GC11289@acer.localdomain>
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	Wang Bo <wang.bo116@zte.com.cn>,
	John Fastabend <john.r.fastabend@intel.com>,
	Eric Dumazet <edumazet@google.com>,
	Terry Lam <vtlam@google.com>
To: Cong Wang <cwang@twopensource.com>
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On Fri, Oct 24, 2014 at 05:38:48PM -0700, Cong Wang wrote:
> On Fri, Oct 24, 2014 at 5:36 PM, Patrick McHardy <kaber@trash.net> wrote:
> >
> > Again, the correct fix is to make qdisc_create_dflt() not call
> > qdisc_destroy() but clean up the qdisc manually as done in
> > qdisc_create().
> 
> I kindly wish you a good luck with fixing all callers of qdisc_create_dflt().
> Go ahead. :)

Here you go:

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index fc04fe9..3a71e51 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -590,18 +590,21 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 	struct Qdisc *sch;
 
 	if (!try_module_get(ops->owner))
-		goto errout;
+		goto err1;
 
 	sch = qdisc_alloc(dev_queue, ops);
 	if (IS_ERR(sch))
-		goto errout;
+		goto err2;
 	sch->parent = parentid;
 
 	if (!ops->init || ops->init(sch, NULL) == 0)
 		return sch;
 
-	qdisc_destroy(sch);
-errout:
+	dev_put(sch->dev_queue->dev);
+	kfree((char *)sch - sch->padded);
+err2:
+	module_put(ops->owner);
+err1:
 	return NULL;
 }
 EXPORT_SYMBOL(qdisc_create_dflt);