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-rw-r--r--include/net/pkt_sched.h7
-rw-r--r--net/core/dev.c26
-rw-r--r--net/sched/sch_generic.c4
3 files changed, 26 insertions, 11 deletions
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index f5c1bee0cd6a..6d7b12cba015 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -128,12 +128,7 @@ void __qdisc_run(struct Qdisc *q);
static inline void qdisc_run(struct Qdisc *q)
{
if (qdisc_run_begin(q)) {
- /* NOLOCK qdisc must check 'state' under the qdisc seqlock
- * to avoid racing with dev_qdisc_reset()
- */
- if (!(q->flags & TCQ_F_NOLOCK) ||
- likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
- __qdisc_run(q);
+ __qdisc_run(q);
qdisc_run_end(q);
}
}
diff --git a/net/core/dev.c b/net/core/dev.c
index 222b1d322c96..d596cd746353 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5025,25 +5025,43 @@ static __latent_entropy void net_tx_action(struct softirq_action *h)
sd->output_queue_tailp = &sd->output_queue;
local_irq_enable();
+ rcu_read_lock();
+
while (head) {
struct Qdisc *q = head;
spinlock_t *root_lock = NULL;
head = head->next_sched;
- if (!(q->flags & TCQ_F_NOLOCK)) {
- root_lock = qdisc_lock(q);
- spin_lock(root_lock);
- }
/* We need to make sure head->next_sched is read
* before clearing __QDISC_STATE_SCHED
*/
smp_mb__before_atomic();
+
+ if (!(q->flags & TCQ_F_NOLOCK)) {
+ root_lock = qdisc_lock(q);
+ spin_lock(root_lock);
+ } else if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED,
+ &q->state))) {
+ /* There is a synchronize_net() between
+ * STATE_DEACTIVATED flag being set and
+ * qdisc_reset()/some_qdisc_is_busy() in
+ * dev_deactivate(), so we can safely bail out
+ * early here to avoid data race between
+ * qdisc_deactivate() and some_qdisc_is_busy()
+ * for lockless qdisc.
+ */
+ clear_bit(__QDISC_STATE_SCHED, &q->state);
+ continue;
+ }
+
clear_bit(__QDISC_STATE_SCHED, &q->state);
qdisc_run(q);
if (root_lock)
spin_unlock(root_lock);
}
+
+ rcu_read_unlock();
}
xfrm_dev_backlog(sd);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 795d986e7030..d86c4cca2cab 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1177,8 +1177,10 @@ static void dev_reset_queue(struct net_device *dev,
qdisc_reset(qdisc);
spin_unlock_bh(qdisc_lock(qdisc));
- if (nolock)
+ if (nolock) {
+ clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
spin_unlock_bh(&qdisc->seqlock);
+ }
}
static bool some_qdisc_is_busy(struct net_device *dev)