examples/vhost: verify strdup return

[ upstream commit b119863bd6643558af3ac3b39a63b6524e7545eb ]

Add verify strdup return value logic.

Fixes: 53d3f47 ("vhost: integrate dmadev in asynchronous data-path")

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Huisong Li <lihuisong@huawei.com>

examples/vhost/main.c

@@ -259,6 +259,9 @@ open_dma(const char *value)
 	char *dma_arg[RTE_MAX_VHOST_DEVICE];
 	int args_nr;
 
+	if (input == NULL)
+		return -1;
+
 	while (isblank(*addrs))
 		addrs++;
 	if (*addrs == '\0') {