scsi: libcxgbi: Fix a use after free in cxgbi_conn_xmit_pdu()

We accidentally move this logging printk after the free, but that leads to
a use after free.

Link: https://lore.kernel.org/r/20200824085933.GD208317@mwanda
Fixes: e33c2482 ("scsi: cxgb4i: Add support for iSCSI segmentation offload")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/cxgbi/libcxgbi.c

@@ -2457,10 +2457,10 @@ int cxgbi_conn_xmit_pdu(struct iscsi_task *task)
 		return err;
 	}
 
-	__kfree_skb(skb);
 	log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_PDU_TX,
 		  "itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n",
 		  task->itt, skb, skb->len, skb->data_len, err);
+	__kfree_skb(skb);
 	iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err);
 	iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED);
 	return err;