[NET_SCHED]: sch_htb/sch_hfsc: fix oops in qlen_notify

[NET_SCHED]: sch_htb/sch_hfsc: fix oops in qlen_notify

[Patrick McHardy]

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Fix fallout from my qdisc endless loop fixes. I've checked
all qdiscs, these two should be the only broken ones.
The patch applies to current -git and the last -stable.


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[NET_SCHED]: sch_htb/sch_hfsc: fix oops in qlen_notify

During both HTB and HFSC class deletion the class is removed from the
class hash before calling qdisc_tree_decrease_qlen. This makes the
->get operation in qdisc_tree_decrease_qlen fail, so it passes a NULL
pointer to ->qlen_notify, causing an oops.

Signed-off-by: Patrick McHardy <kaber@trash.net>

---
commit 36ab004c1021c259b8780834287494fe630fc9ee
tree cad66b55dd7c6954ff9b55b16f791d7474adf6b0
parent 703071b5b93d88d5acb0edd5b9dd86c69ad970f2
author Patrick McHardy <kaber@trash.net> Tue, 27 Mar 2007 17:07:50 +0200
committer Patrick McHardy <kaber@trash.net> Tue, 27 Mar 2007 18:25:42 +0200

 net/sched/sch_hfsc.c |    4 +++-
 net/sched/sch_htb.c  |    6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 396deb7..407c6fb 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1184,10 +1184,12 @@ hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
 
 	sch_tree_lock(sch);
 
-	list_del(&cl->hlist);
 	list_del(&cl->siblings);
 	hfsc_adjust_levels(cl->cl_parent);
+
 	hfsc_purge_queue(sch, cl);
+	list_del(&cl->hlist);
+
 	if (--cl->refcnt == 0)
 		hfsc_destroy_class(sch, cl);
 
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 97cbb9a..3c3294d 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1380,15 +1380,15 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg)
 
 	sch_tree_lock(sch);
 
-	/* delete from hash and active; remainder in destroy_class */
-	hlist_del_init(&cl->hlist);
-
 	if (!cl->level) {
 		qlen = cl->un.leaf.q->q.qlen;
 		qdisc_reset(cl->un.leaf.q);
 		qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
 	}
 
+	/* delete from hash and active; remainder in destroy_class */
+	hlist_del_init(&cl->hlist);
+
 	if (cl->prio_activity)
 		htb_deactivate(q, cl);
 

Re: [NET_SCHED]: sch_htb/sch_hfsc: fix oops in qlen_notify

[David Miller]

From: Patrick McHardy <kaber@trash.net>
Date: Tue, 27 Mar 2007 18:28:48 +0200

> Fix fallout from my qdisc endless loop fixes. I've checked
> all qdiscs, these two should be the only broken ones.
> The patch applies to current -git and the last -stable.

Applied, thanks Patrick.