[PATCH net] net: stmmac: clear stale buf->page after recycling on skb build failure

[Lorenzo Bianconi]

In stmmac_rx(), when napi_build_skb() fails the descriptor page is
recycled back to the page pool with page_pool_recycle_direct(), but
buf->page is left pointing at the recycled page, unlike every other
consumption site in the function which clears the pointer after handing
the page away.

With the stale pointer stmmac_rx_refill() skips the replacement
allocation and programs the already-recycled page back into the RX
descriptor.

Clear buf->page on the napi_build_skb() failure path to keep the buffer
lifecycle consistent with the other consumption sites.

Fixes: df542f669307 ("net: stmmac: Switch to zero-copy in non-XDP RX path")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at oss.qualcomm.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 1fb5f804ea23..11035b7d944e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5887,6 +5887,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 			if (!skb) {
 				page_pool_recycle_direct(rx_q->page_pool,
 							 buf->page);
+				buf->page = NULL;
 				rx_dropped++;
 				count++;
 				goto drain_data;

---
base-commit: 1e24c4f2ee44be0eee94092b5d13cbdb4bdf0d60
change-id: 20260921-stmmac-fix-napi-build-skb-error-a02a3e839bd9

Best regards,
-- 
Lorenzo Bianconi <lorenzo.bianconi at oss.qualcomm.com>