tty: serial: 8250: serial_cs: Fix a memory leak in error handling path

stable inclusion
from linux-4.19.198
commit cddee5c287e26f6b2ba5c0ffdfc3a846f2f10461

--------------------------------

[ Upstream commit fad92b11 ]

In the probe function, if the final 'serial_config()' fails, 'info' is
leaking.

Add a resource handling path to free this memory.
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/dc25f96b7faebf42e60fe8d02963c941cf4d8124.1621971720.git.christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/tty/serial/8250/serial_cs.c

@@ -306,6 +306,7 @@ static int serial_resume(struct pcmcia_device *link)
 static int serial_probe(struct pcmcia_device *link)
 {
 	struct serial_info *info;
+	int ret;
 
 	dev_dbg(&link->dev, "serial_attach()\n");
 
@@ -320,7 +321,15 @@ static int serial_probe(struct pcmcia_device *link)
 	if (do_sound)
 		link->config_flags |= CONF_ENABLE_SPKR;
 
-	return serial_config(link);
+	ret = serial_config(link);
+	if (ret)
+		goto free_info;
+
+	return 0;
+
+free_info:
+	kfree(info);
+	return ret;
 }
 
 static void serial_detach(struct pcmcia_device *link)