Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Martin KaFai Lau says:

====================
pull-request: bpf-next 2025-05-02

We've added 14 non-merge commits during the last 10 day(s) which contain
a total of 13 files changed, 740 insertions(+), 121 deletions(-).

The main changes are:

1) Avoid skipping or repeating a sk when using a UDP bpf_iter,
   from Jordan Rife.

2) Fixed a crash when a bpf qdisc is set in
   the net.core.default_qdisc, from Amery Hung.

3) A few other fixes in the bpf qdisc, from Amery Hung.
   - Always call qdisc_watchdog_init() in the .init prologue such that
     the .reset/.destroy epilogue can always call qdisc_watchdog_cancel()
     without issue.
   - bpf_qdisc_init_prologue() was incorrectly returning an error
     when the bpf qdisc is set as the default_qdisc and the mq is creating
     the default_qdisc. It is now fixed.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  selftests/bpf: Cleanup bpf qdisc selftests
  selftests/bpf: Test attaching a bpf qdisc with incomplete operators
  bpf: net_sched: Make some Qdisc_ops ops mandatory
  selftests/bpf: Test setting and creating bpf qdisc as default qdisc
  bpf: net_sched: Fix bpf qdisc init prologue when set as default qdisc
  selftests/bpf: Add tests for bucket resume logic in UDP socket iterators
  selftests/bpf: Return socket cookies from sock_iter_batch progs
  bpf: udp: Avoid socket skips and repeats during iteration
  bpf: udp: Use bpf_udp_iter_batch_item for bpf_udp_iter_state batch items
  bpf: udp: Get rid of st_bucket_done
  bpf: udp: Make sure iter->batch always contains a full bucket snapshot
  bpf: udp: Make mem flags configurable through bpf_iter_udp_realloc_batch
  bpf: net_sched: Fix using bpf qdisc as default qdisc
  selftests/bpf: Fix compilation errors
====================

Link: https://patch.msgid.link/20250503010755.4030524-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 23 insertions, 9 deletions

diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c
index 9f32b305636f..7ea8b54b2ab1 100644
--- a/net/sched/bpf_qdisc.c
+++ b/net/sched/bpf_qdisc.c
@@ -234,18 +234,20 @@ __bpf_kfunc int bpf_qdisc_init_prologue(struct Qdisc *sch,
 	struct net_device *dev = qdisc_dev(sch);
 	struct Qdisc *p;
 
+	qdisc_watchdog_init(&q->watchdog, sch);
+
 	if (sch->parent != TC_H_ROOT) {
+		/* If qdisc_lookup() returns NULL, it means .init is called by
+		 * qdisc_create_dflt() in mq/mqprio_init and the parent qdisc
+		 * has not been added to qdisc_hash yet.
+		 */
 		p = qdisc_lookup(dev, TC_H_MAJ(sch->parent));
-		if (!p)
-			return -ENOENT;
-
-		if (!(p->flags & TCQ_F_MQROOT)) {
+		if (p && !(p->flags & TCQ_F_MQROOT)) {
 			NL_SET_ERR_MSG(extack, "BPF qdisc only supported on root or mq");
 			return -EINVAL;
 		}
 	}
 
-	qdisc_watchdog_init(&q->watchdog, sch);
 	return 0;
 }
 
@@ -393,6 +395,17 @@ static void bpf_qdisc_unreg(void *kdata, struct bpf_link *link)
 	return unregister_qdisc(kdata);
 }
 
+static int bpf_qdisc_validate(void *kdata)
+{
+	struct Qdisc_ops *ops = (struct Qdisc_ops *)kdata;
+
+	if (!ops->enqueue || !ops->dequeue || !ops->init ||
+	    !ops->reset || !ops->destroy)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int Qdisc_ops__enqueue(struct sk_buff *skb__ref, struct Qdisc *sch,
 			      struct sk_buff **to_free)
 {
@@ -430,6 +443,7 @@ static struct bpf_struct_ops bpf_Qdisc_ops = {
 	.verifier_ops = &bpf_qdisc_verifier_ops,
 	.reg = bpf_qdisc_reg,
 	.unreg = bpf_qdisc_unreg,
+	.validate = bpf_qdisc_validate,
 	.init_member = bpf_qdisc_init_member,
 	.init = bpf_qdisc_init,
 	.name = "Qdisc_ops",
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index db6330258dda..c5e3673aadbe 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -208,7 +208,7 @@ static struct Qdisc_ops *qdisc_lookup_default(const char *name)
 
 	for (q = qdisc_base; q; q = q->next) {
 		if (!strcmp(name, q->id)) {
-			if (!try_module_get(q->owner))
+			if (!bpf_try_module_get(q, q->owner))
 				q = NULL;
 			break;
 		}
@@ -238,7 +238,7 @@ int qdisc_set_default(const char *name)
 
 	if (ops) {
 		/* Set new default */
-		module_put(default_qdisc_ops->owner);
+		bpf_module_put(default_qdisc_ops, default_qdisc_ops->owner);
 		default_qdisc_ops = ops;
 	}
 	write_unlock(&qdisc_mod_lock);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index fc5ef69359db..08e0e3aff976 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1002,14 +1002,14 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 {
 	struct Qdisc *sch;
 
-	if (!try_module_get(ops->owner)) {
+	if (!bpf_try_module_get(ops, ops->owner)) {
 		NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
 		return NULL;
 	}
 
 	sch = qdisc_alloc(dev_queue, ops, extack);
 	if (IS_ERR(sch)) {
-		module_put(ops->owner);
+		bpf_module_put(ops, ops->owner);
 		return NULL;
 	}
 	sch->parent = parentid;