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authorPatrick McHardy <kaber@trash.net>2009-09-09 18:11:23 -0700
committerDavid S. Miller <davem@davemloft.net>2009-09-09 18:11:23 -0700
commit23bcf634c8bc0d84607a5b863333191d58baee4c (patch)
treebc988ab6230bebf47e1dc22db70f94901ac2eeb5 /net/sched
parentea6a634ef7f0ab1d1f48ba0ad4f50e96d6065312 (diff)
net_sched: fix estimator lock selection for mq child qdiscs
When new child qdiscs are attached to the mq qdisc, they are actually attached as root qdiscs to the device queues. The lock selection for new estimators incorrectly picks the root lock of the existing and to be replaced qdisc, which results in a use-after-free once the old qdisc has been destroyed. Mark mq qdisc instances with a new flag and treat qdiscs attached to mq as children similar to regular root qdiscs. Additionally prevent estimators from being attached to the mq qdisc itself since it only updates its byte and packet counters during dumps. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_api.c42
-rw-r--r--net/sched/sch_mq.c1
2 files changed, 27 insertions, 16 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 2a78d541015..3af106140f3 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -733,7 +733,8 @@ static struct lock_class_key qdisc_rx_lock;
static struct Qdisc *
qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
- u32 parent, u32 handle, struct nlattr **tca, int *errp)
+ struct Qdisc *p, u32 parent, u32 handle,
+ struct nlattr **tca, int *errp)
{
int err;
struct nlattr *kind = tca[TCA_KIND];
@@ -810,24 +811,21 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
if (tca[TCA_RATE]) {
spinlock_t *root_lock;
+ err = -EOPNOTSUPP;
+ if (sch->flags & TCQ_F_MQROOT)
+ goto err_out4;
+
if ((sch->parent != TC_H_ROOT) &&
- !(sch->flags & TCQ_F_INGRESS))
+ !(sch->flags & TCQ_F_INGRESS) &&
+ (!p || !(p->flags & TCQ_F_MQROOT)))
root_lock = qdisc_root_sleeping_lock(sch);
else
root_lock = qdisc_lock(sch);
err = gen_new_estimator(&sch->bstats, &sch->rate_est,
root_lock, tca[TCA_RATE]);
- if (err) {
- /*
- * Any broken qdiscs that would require
- * a ops->reset() here? The qdisc was never
- * in action so it shouldn't be necessary.
- */
- if (ops->destroy)
- ops->destroy(sch);
- goto err_out3;
- }
+ if (err)
+ goto err_out4;
}
qdisc_list_add(sch);
@@ -843,6 +841,15 @@ err_out2:
err_out:
*errp = err;
return NULL;
+
+err_out4:
+ /*
+ * Any broken qdiscs that would require a ops->reset() here?
+ * The qdisc was never in action so it shouldn't be necessary.
+ */
+ if (ops->destroy)
+ ops->destroy(sch);
+ goto err_out3;
}
static int qdisc_change(struct Qdisc *sch, struct nlattr **tca)
@@ -867,13 +874,16 @@ static int qdisc_change(struct Qdisc *sch, struct nlattr **tca)
qdisc_put_stab(sch->stab);
sch->stab = stab;
- if (tca[TCA_RATE])
+ if (tca[TCA_RATE]) {
/* NB: ignores errors from replace_estimator
because change can't be undone. */
+ if (sch->flags & TCQ_F_MQROOT)
+ goto out;
gen_replace_estimator(&sch->bstats, &sch->rate_est,
qdisc_root_sleeping_lock(sch),
tca[TCA_RATE]);
-
+ }
+out:
return 0;
}
@@ -1097,7 +1107,7 @@ create_n_graft:
if (!(n->nlmsg_flags&NLM_F_CREATE))
return -ENOENT;
if (clid == TC_H_INGRESS)
- q = qdisc_create(dev, &dev->rx_queue,
+ q = qdisc_create(dev, &dev->rx_queue, p,
tcm->tcm_parent, tcm->tcm_parent,
tca, &err);
else {
@@ -1106,7 +1116,7 @@ create_n_graft:
if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
ntx = p->ops->cl_ops->select_queue(p, tcm);
- q = qdisc_create(dev, netdev_get_tx_queue(dev, ntx),
+ q = qdisc_create(dev, netdev_get_tx_queue(dev, ntx), p,
tcm->tcm_parent, tcm->tcm_handle,
tca, &err);
}
diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c
index c84dec9c8c7..dd5ee022f1f 100644
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -64,6 +64,7 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt)
priv->qdiscs[ntx] = qdisc;
}
+ sch->flags |= TCQ_F_MQROOT;
return 0;
err: