[patch 1/3] net: serialize hrtimer callback in sched_cbq

[Thomas Gleixner <tglx@linutronix.de>]

[-- Attachment #1: net-sched-cbq-serialize-hrtimer-callback.patch --]
[-- Type: text/plain, Size: 1956 bytes --]

The hrtimer callback cbq_undelay() is not serialized against
cbq_ovl_delay(). That affects at least q->pmask and q->delay_timer.

Lock it proper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 net/sched/sch_cbq.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Index: linux-2.6/net/sched/sch_cbq.c
===================================================================
--- linux-2.6.orig/net/sched/sch_cbq.c
+++ linux-2.6/net/sched/sch_cbq.c
@@ -163,6 +163,7 @@ struct cbq_sched_data
 	psched_time_t		now_rt;		/* Cached real time */
 	unsigned		pmask;
 
+	spinlock_t		lock;
 	struct hrtimer		delay_timer;
 	struct qdisc_watchdog	watchdog;	/* Watchdog timer,
 						   started when CBQ has
@@ -503,6 +504,9 @@ static void cbq_ovl_delay(struct cbq_cla
 		cl->undertime = q->now + delay;
 
 		if (delay > 0) {
+			unsigned long flags;
+
+			spin_lock_irqsave(&q->lock, flags);
 			sched += delay + cl->penalty;
 			cl->penalized = sched;
 			cl->cpriority = TC_CBQ_MAXPRIO;
@@ -518,6 +522,7 @@ static void cbq_ovl_delay(struct cbq_cla
 			hrtimer_restart(&q->delay_timer);
 			cl->delayed = 1;
 			cl->xstats.overactions++;
+			spin_unlock_irqrestore(&q->lock, flags);
 			return;
 		}
 		delay = 1;
@@ -599,6 +604,7 @@ static enum hrtimer_restart cbq_undelay(
 
 	now = psched_get_time();
 
+	spin_lock(&q->lock);
 	pmask = q->pmask;
 	q->pmask = 0;
 
@@ -623,6 +629,7 @@ static enum hrtimer_restart cbq_undelay(
 		time = ktime_add_ns(time, PSCHED_TICKS2NS(now + delay));
 		hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS);
 	}
+	spin_unlock(&q->lock);
 
 	sch->flags &= ~TCQ_F_THROTTLED;
 	__netif_schedule(qdisc_root(sch));
@@ -1396,6 +1403,7 @@ static int cbq_init(struct Qdisc *sch, s
 	q->link.avpkt = q->link.allot/2;
 	q->link.minidle = -0x7FFFFFFF;
 
+	spin_lock_init(&q->lock);
 	qdisc_watchdog_init(&q->watchdog, sch);
 	hrtimer_init(&q->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 	q->delay_timer.function = cbq_undelay;