[AMD Official Use Only - AMD Internal Distribution Only]
> -----Original Message-----
> From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Sent: Thursday, August 7, 2025 9:30 PM
> To: Pandey, Radhey Shyam <radhey.shyam.pandey@xxxxxxx>
> Cc: kernel-janitors@xxxxxxxxxxxxxxx
> Subject: [bug report] net: axienet: Introduce dmaengine support
>
> Hello Radhey Shyam Pandey,
>
> Commit 6a91b846af85 ("net: axienet: Introduce dmaengine support") from Nov 16,
> 2023 (linux-next), leads to the following Smatch static checker warning:
>
> drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1171 axienet_dma_rx_cb()
> error: 'app_metadata' dereferencing possible ERR_PTR()
>
> drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> 1156 static void axienet_dma_rx_cb(void *data, const struct dmaengine_result
> *result)
> 1157 {
> 1158 struct skbuf_dma_descriptor *skbuf_dma;
> 1159 size_t meta_len, meta_max_len, rx_len;
> 1160 struct axienet_local *lp = data;
> 1161 struct sk_buff *skb;
> 1162 u32 *app_metadata;
> 1163
> 1164 skbuf_dma = axienet_get_rx_desc(lp, lp->rx_ring_tail++);
> 1165 skb = skbuf_dma->skb;
> 1166 app_metadata = dmaengine_desc_get_metadata_ptr(skbuf_dma-
> >desc, &meta_len,
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> No error checking.
>
> 1167 &meta_max_len);
> 1168 dma_unmap_single(lp->dev, skbuf_dma->dma_address, lp-
> >max_frm_size,
> 1169 DMA_FROM_DEVICE);
> 1170 /* TODO: Derive app word index programmatically */
> --> 1171 rx_len = (app_metadata[LEN_APP] & 0xFFFF);
> ^^^^^^^^^^^^
> Dereference.
>
> 1172 skb_put(skb, rx_len);
> 1173 skb->protocol = eth_type_trans(skb, lp->ndev);
> 1174 skb->ip_summed = CHECKSUM_NONE;
> 1175
> 1176 __netif_rx(skb);
> 1177 u64_stats_update_begin(&lp->rx_stat_sync);
> 1178 u64_stats_add(&lp->rx_packets, 1);
> 1179 u64_stats_add(&lp->rx_bytes, rx_len);
> 1180 u64_stats_update_end(&lp->rx_stat_sync);
> 1181 axienet_rx_submit_desc(lp->ndev);
> 1182 dma_async_issue_pending(lp->rx_chan);
> 1183 }
>
Thanks. I acknowledge it and Suraj (added in CC)
will send out fix for it.
-Radhey
