net: hold netdev instance lock during qdisc ndo_setup_tc

Qdisc operations that can lead to ndo_setup_tc might need
to have an instance lock. Add netdev_lock_ops/netdev_unlock_ops
invocations for all psched_rtnl_msg_handlers operations.

Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Saeed Mahameed <saeed@kernel.org>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250305163732.2766420-5-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 21940f3ae66f9adc16ccda25f264151ce1dd1b8f..f5101c2ffc664baf591a128e196cb230b29d13af 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1279,9 +1279,11 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
                         * We replay the request because the device may
                         * go away in the mean time.
                         */
+                       netdev_unlock_ops(dev);
                        rtnl_unlock();
                        request_module(NET_SCH_ALIAS_PREFIX "%s", name);
                        rtnl_lock();
+                       netdev_lock_ops(dev);
                        ops = qdisc_lookup_ops(kind);
                        if (ops != NULL) {
                                /* We will try again qdisc_lookup_ops,
@@ -1591,7 +1593,11 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
        if (!dev)
                return -ENODEV;
 
-       return __tc_get_qdisc(skb, n, extack, dev, tca, tcm);
+       netdev_lock_ops(dev);
+       err = __tc_get_qdisc(skb, n, extack, dev, tca, tcm);
+       netdev_unlock_ops(dev);
+
+       return err;
 }
 
 static bool req_create_or_replace(struct nlmsghdr *n)
@@ -1828,7 +1834,9 @@ replay:
                return -ENODEV;
 
        replay = false;
+       netdev_lock_ops(dev);
        err = __tc_modify_qdisc(skb, n, extack, dev, tca, tcm, &replay);
+       netdev_unlock_ops(dev);
        if (replay)
                goto replay;
 
@@ -1919,17 +1927,23 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
                        s_q_idx = 0;
                q_idx = 0;
 
+               netdev_lock_ops(dev);
                if (tc_dump_qdisc_root(rtnl_dereference(dev->qdisc),
                                       skb, cb, &q_idx, s_q_idx,
-                                      true, tca[TCA_DUMP_INVISIBLE]) < 0)
+                                      true, tca[TCA_DUMP_INVISIBLE]) < 0) {
+                       netdev_unlock_ops(dev);
                        goto done;
+               }
 
                dev_queue = dev_ingress_queue(dev);
                if (dev_queue &&
                    tc_dump_qdisc_root(rtnl_dereference(dev_queue->qdisc_sleeping),
                                       skb, cb, &q_idx, s_q_idx, false,
-                                      tca[TCA_DUMP_INVISIBLE]) < 0)
+                                      tca[TCA_DUMP_INVISIBLE]) < 0) {
+                       netdev_unlock_ops(dev);
                        goto done;
+               }
+               netdev_unlock_ops(dev);
 
 cont:
                idx++;
@@ -2308,7 +2322,11 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
        if (!dev)
                return -ENODEV;
 
-       return __tc_ctl_tclass(skb, n, extack, dev, tca, tcm);
+       netdev_lock_ops(dev);
+       err = __tc_ctl_tclass(skb, n, extack, dev, tca, tcm);
+       netdev_unlock_ops(dev);
+
+       return err;
 }
 
 struct qdisc_dump_args {
@@ -2426,7 +2444,9 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
        if (!dev)
                return 0;
 
+       netdev_lock_ops(dev);
        err = __tc_dump_tclass(skb, cb, tcm, dev);
+       netdev_unlock_ops(dev);
 
        dev_put(dev);