4.9-stable patches

[thirdparty/kernel/stable-queue.git] / releases / 3.3.4 / net_sched-gred-fix-oops-in-gred_dump-in-wred-mode.patch

From d65ba13406233f881bc212640b54bbb87c52141b Mon Sep 17 00:00:00 2001
From: David Ward <david.ward@ll.mit.edu>
Date: Sun, 15 Apr 2012 12:31:45 +0000
Subject: [PATCH 19/28] net_sched: gred: Fix oops in gred_dump() in WRED mode


From: David Ward <david.ward@ll.mit.edu>

[ Upstream commit 244b65dbfede788f2fa3fe2463c44d0809e97c6b ]

A parameter set exists for WRED mode, called wred_set, to hold the same
values for qavg and qidlestart across all VQs. The WRED mode values had
been previously held in the VQ for the default DP. After these values
were moved to wred_set, the VQ for the default DP was no longer created
automatically (so that it could be omitted on purpose, to have packets
in the default DP enqueued directly to the device without using RED).

However, gred_dump() was overlooked during that change; in WRED mode it
still reads qavg/qidlestart from the VQ for the default DP, which might
not even exist. As a result, this command sequence will cause an oops:

tc qdisc add dev $DEV handle $HANDLE parent $PARENT gred setup \
    DPs 3 default 2 grio
tc qdisc change dev $DEV handle $HANDLE gred DP 0 prio 8 $RED_OPTIONS
tc qdisc change dev $DEV handle $HANDLE gred DP 1 prio 8 $RED_OPTIONS

This fixes gred_dump() in WRED mode to use the values held in wred_set.

Signed-off-by: David Ward <david.ward@ll.mit.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sched/sch_gred.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -565,11 +565,8 @@ static int gred_dump(struct Qdisc *sch,
 		opt.packets	= q->packetsin;
 		opt.bytesin	= q->bytesin;
 
-		if (gred_wred_mode(table)) {
-			q->vars.qidlestart =
-				table->tab[table->def]->vars.qidlestart;
-			q->vars.qavg = table->tab[table->def]->vars.qavg;
-		}
+		if (gred_wred_mode(table))
+			gred_load_wred_set(table, q);
 
 		opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);