From: David S. Miller Date: Sun, 3 Aug 2008 03:02:43 +0000 (-0700) Subject: pkt_sched: Use qdisc_lock() on already sampled root qdisc. X-Git-Tag: v2.6.27-rc2~2^2~22 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5fb662297b8a4bdadd60371c34b760efca948ebc;p=linux-2.6 pkt_sched: Use qdisc_lock() on already sampled root qdisc. Based upon a bug report by Jeff Kirsher. Don't use qdisc_root_lock() in these cases as the root qdisc could have been changed, and we'd thus lock the wrong object. Tested by Emil S Tantilov who confirms that this seems to fix the problem. Signed-off-by: David S. Miller --- diff --git a/net/core/dev.c b/net/core/dev.c index 69320a56a0..da7acacf02 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1796,7 +1796,7 @@ gso: skb->tc_verd = SET_TC_AT(skb->tc_verd,AT_EGRESS); #endif if (q->enqueue) { - spinlock_t *root_lock = qdisc_root_lock(q); + spinlock_t *root_lock = qdisc_lock(q); spin_lock(root_lock); @@ -1995,7 +1995,7 @@ static void net_tx_action(struct softirq_action *h) smp_mb__before_clear_bit(); clear_bit(__QDISC_STATE_SCHED, &q->state); - root_lock = qdisc_root_lock(q); + root_lock = qdisc_lock(q); if (spin_trylock(root_lock)) { qdisc_run(q); spin_unlock(root_lock); diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 9c9cd4d948..7cf83b3745 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -29,7 +29,7 @@ /* Main transmission queue. */ /* Modifications to data participating in scheduling must be protected with - * qdisc_root_lock(qdisc) spinlock. + * qdisc_lock(qdisc) spinlock. * * The idea is the following: * - enqueue, dequeue are serialized via qdisc root lock @@ -126,7 +126,7 @@ static inline int qdisc_restart(struct Qdisc *q) if (unlikely((skb = dequeue_skb(q)) == NULL)) return 0; - root_lock = qdisc_root_lock(q); + root_lock = qdisc_lock(q); /* And release qdisc */ spin_unlock(root_lock); @@ -507,7 +507,7 @@ errout: } EXPORT_SYMBOL(qdisc_create_dflt); -/* Under qdisc_root_lock(qdisc) and BH! */ +/* Under qdisc_lock(qdisc) and BH! */ void qdisc_reset(struct Qdisc *qdisc) { @@ -543,7 +543,7 @@ static void __qdisc_destroy(struct rcu_head *head) kfree((char *) qdisc - qdisc->padded); } -/* Under qdisc_root_lock(qdisc) and BH! */ +/* Under qdisc_lock(qdisc) and BH! */ void qdisc_destroy(struct Qdisc *qdisc) { @@ -659,7 +659,7 @@ static bool some_qdisc_is_running(struct net_device *dev, int lock) dev_queue = netdev_get_tx_queue(dev, i); q = dev_queue->qdisc; - root_lock = qdisc_root_lock(q); + root_lock = qdisc_lock(q); if (lock) spin_lock_bh(root_lock); @@ -735,7 +735,7 @@ static void shutdown_scheduler_queue(struct net_device *dev, struct Qdisc *qdisc_default = _qdisc_default; if (qdisc) { - spinlock_t *root_lock = qdisc_root_lock(qdisc); + spinlock_t *root_lock = qdisc_lock(qdisc); dev_queue->qdisc = qdisc_default; dev_queue->qdisc_sleeping = qdisc_default;