can: mcp251xfd: mcp251xfd_handle_rxif_one(): fix wrong NULL pointer check

[ Upstream commit ca4c6eb ]

If alloc_canfd_skb() returns NULL, 'cfg' is an uninitialized variable, so we
should check 'skb' rather than 'cfd' after calling alloc_canfd_skb(priv->ndev,
&cfd).

Fixes: 55e5b97 ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Signed-off-by: Qinglang Miao <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Qinglang Miao

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

@@ -1432,7 +1432,7 @@ mcp251xfd_handle_rxif_one(struct mcp251xfd_priv *priv,
 	else
 		skb = alloc_can_skb(priv->ndev, (struct can_frame **)&cfd);
 
-	if (!cfd) {
+	if (!skb) {
 		stats->rx_dropped++;
 		return 0;
 	}