4 files changed, 35 insertions, 13 deletions

diff --git a/net/core/devmem.c b/net/core/devmem.c
index d9de31a6cc7f..1d04754bc756 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -17,6 +17,7 @@
 #include <net/page_pool/helpers.h>
 #include <net/page_pool/memory_provider.h>
 #include <net/sock.h>
+#include <net/tcp.h>
 #include <trace/events/page_pool.h>
 
 #include "devmem.h"
@@ -357,7 +358,8 @@ struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk,
 							 unsigned int dmabuf_id)
 {
 	struct net_devmem_dmabuf_binding *binding;
-	struct dst_entry *dst = __sk_dst_get(sk);
+	struct net_device *dst_dev;
+	struct dst_entry *dst;
 	int err = 0;
 
 	binding = net_devmem_lookup_dmabuf(dmabuf_id);
@@ -366,16 +368,35 @@ struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk,
 		goto out_err;
 	}
 
+	rcu_read_lock();
+	dst = __sk_dst_get(sk);
+	/* If dst is NULL (route expired), attempt to rebuild it. */
+	if (unlikely(!dst)) {
+		if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk)) {
+			err = -EHOSTUNREACH;
+			goto out_unlock;
+		}
+		dst = __sk_dst_get(sk);
+		if (unlikely(!dst)) {
+			err = -ENODEV;
+			goto out_unlock;
+		}
+	}
+
 	/* The dma-addrs in this binding are only reachable to the corresponding
 	 * net_device.
 	 */
-	if (!dst || !dst->dev || dst->dev->ifindex != binding->dev->ifindex) {
+	dst_dev = dst_dev_rcu(dst);
+	if (unlikely(!dst_dev) || unlikely(dst_dev != binding->dev)) {
 		err = -ENODEV;
-		goto out_err;
+		goto out_unlock;
 	}
 
+	rcu_read_unlock();
 	return binding;
 
+out_unlock:
+	rcu_read_unlock();
 out_err:
 	if (binding)
 		net_devmem_dmabuf_binding_put(binding);
diff --git a/net/core/filter.c b/net/core/filter.c
index 76628df1fc82..fa06c5a08e22 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3877,7 +3877,8 @@ static inline int __bpf_skb_change_head(struct sk_buff *skb, u32 head_room,
 	u32 new_len = skb->len + head_room;
 	int ret;
 
-	if (unlikely(flags || (!skb_is_gso(skb) && new_len > max_len) ||
+	if (unlikely(flags || (int)head_room < 0 ||
+		     (!skb_is_gso(skb) && new_len > max_len) ||
 		     new_len < skb->len))
 		return -EINVAL;
 
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c
index fd57b845de33..a725d21159a6 100644
--- a/net/core/gro_cells.c
+++ b/net/core/gro_cells.c
@@ -60,9 +60,10 @@ static int gro_cell_poll(struct napi_struct *napi, int budget)
 	struct sk_buff *skb;
 	int work_done = 0;
 
-	__local_lock_nested_bh(&cell->bh_lock);
 	while (work_done < budget) {
+		__local_lock_nested_bh(&cell->bh_lock);
 		skb = __skb_dequeue(&cell->napi_skbs);
+		__local_unlock_nested_bh(&cell->bh_lock);
 		if (!skb)
 			break;
 		napi_gro_receive(napi, skb);
@@ -71,7 +72,6 @@ static int gro_cell_poll(struct napi_struct *napi, int budget)
 
 	if (work_done < budget)
 		napi_complete_done(napi, work_done);
-	__local_unlock_nested_bh(&cell->bh_lock);
 	return work_done;
 }
 
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 60a05d3b7c24..331764845e8f 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -228,19 +228,16 @@ static void refill_skbs(struct netpoll *np)
 {
 	struct sk_buff_head *skb_pool;
 	struct sk_buff *skb;
-	unsigned long flags;
 
 	skb_pool = &np->skb_pool;
 
-	spin_lock_irqsave(&skb_pool->lock, flags);
-	while (skb_pool->qlen < MAX_SKBS) {
+	while (READ_ONCE(skb_pool->qlen) < MAX_SKBS) {
 		skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 		if (!skb)
 			break;
 
-		__skb_queue_tail(skb_pool, skb);
+		skb_queue_tail(skb_pool, skb);
 	}
-	spin_unlock_irqrestore(&skb_pool->lock, flags);
 }
 
 static void zap_completion_queue(void)
@@ -814,6 +811,10 @@ static void __netpoll_cleanup(struct netpoll *np)
 	if (!npinfo)
 		return;
 
+	/* At this point, there is a single npinfo instance per netdevice, and
+	 * its refcnt tracks how many netpoll structures are linked to it. We
+	 * only perform npinfo cleanup when the refcnt decrements to zero.
+	 */
 	if (refcount_dec_and_test(&npinfo->refcnt)) {
 		const struct net_device_ops *ops;
 
@@ -823,8 +824,7 @@ static void __netpoll_cleanup(struct netpoll *np)
 
 		RCU_INIT_POINTER(np->dev->npinfo, NULL);
 		call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
-	} else
-		RCU_INIT_POINTER(np->dev->npinfo, NULL);
+	}
 
 	skb_pool_flush(np);
 }