net: qrtr: Fix memory leak on qrtr_tx_wait failure

qrtr_tx_wait does not check for radix_tree_insert failure, causing
the 'flow' object to be unreferenced after qrtr_tx_wait return. Fix
that by releasing flow on radix_tree_insert failure.

Fixes: 5fdeb0d3 ("net: qrtr: Implement outgoing flow control")
Reported-by: syzbot+739016799a89c530b32a@syzkaller.appspotmail.com
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/qrtr/qrtr.c

@@ -271,7 +271,10 @@ static int qrtr_tx_wait(struct qrtr_node *node, int dest_node, int dest_port,
 		flow = kzalloc(sizeof(*flow), GFP_KERNEL);
 		if (flow) {
 			init_waitqueue_head(&flow->resume_tx);
-			radix_tree_insert(&node->qrtr_tx_flow, key, flow);
+			if (radix_tree_insert(&node->qrtr_tx_flow, key, flow)) {
+				kfree(flow);
+				flow = NULL;
+			}
 		}
 	}
 	mutex_unlock(&node->qrtr_tx_lock);