sch_qfq: fix overflow in qfq_update_start()

grp->slot_shift is between 22 and 41, so using 32bit wide variables is probably a typo. This could explain QFQ hangs Dave reported to me, after 2^23 packets ? (23 = 64 - 41) Reported-by: Dave Taht <[email protected]> Signed-off-by: Eric Dumazet <[email protected]> CC: Stephen Hemminger <[email protected]> CC: Dave Taht <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mna · Jan 3, 2012 · 6bafcac · 6bafcac
1 parent 115e8e7
commit 6bafcac
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
@@ -817,11 +817,11 @@ static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
 static void qfq_update_start(struct qfq_sched *q, struct qfq_class *cl)
 {
 	unsigned long mask;
-	uint32_t limit, roundedF;
+	u64 limit, roundedF;
 	int slot_shift = cl->grp->slot_shift;
 
 	roundedF = qfq_round_down(cl->F, slot_shift);
-	limit = qfq_round_down(q->V, slot_shift) + (1UL << slot_shift);
+	limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift);
 
 	if (!qfq_gt(cl->F, q->V) || qfq_gt(roundedF, limit)) {
 		/* timestamp was stale */