Hello Yue Haibing,
Commit c824125cbb18 ("ixgbe: Fix passing 0 to ERR_PTR in
ixgbe_run_xdp()") from Jan 6, 2025 (linux-next), leads to the
following Smatch static checker warning:
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:2108 ixgbe_put_rx_buffer()
warn: possible NULL dereference of 'skb'
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
2099 static void ixgbe_put_rx_buffer(struct ixgbe_ring *rx_ring,
2100 struct ixgbe_rx_buffer *rx_buffer,
2101 struct sk_buff *skb,
2102 int rx_buffer_pgcnt)
2103 {
2104 if (ixgbe_can_reuse_rx_page(rx_buffer, rx_buffer_pgcnt)) {
2105 /* hand second half of page back to the ring */
2106 ixgbe_reuse_rx_page(rx_ring, rx_buffer);
2107 } else {
--> 2108 if (!IS_ERR(skb) && IXGBE_CB(skb)->dma ==
rx_buffer->dma) {
^^^
This can't be an error pointer and probably it should be a NULL check.
I'm not sure if your patch introduced this issue or just exposed it.
2109 /* the page has been released from the ring */
2110 IXGBE_CB(skb)->page_released = true;
2111 } else {
2112 /* we are not reusing the buffer so unmap it */
2113 dma_unmap_page_attrs(rx_ring->dev,
rx_buffer->dma,
2114 ixgbe_rx_pg_size(rx_ring),
2115 DMA_FROM_DEVICE,
2116 IXGBE_RX_DMA_ATTR);
2117 }
2118 __page_frag_cache_drain(rx_buffer->page,
2119 rx_buffer->pagecnt_bias);
2120 }
2121
2122 /* clear contents of rx_buffer */
2123 rx_buffer->page = NULL;
2124 rx_buffer->skb = NULL;
2125 }
regards,
dan carpenter
