From: Arumuga Durai A <cadurai@codeaurora.org>
Date: Thu, 5 May 2016 07:23:29 +0000 (+0530)
Subject: USB: gadget: serial: Fix debugfs crash
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=9ac17853930c9db6feafc80d50ac200eb67a71cc;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

USB: gadget: serial: Fix debugfs crash

Serial function driver creates debugfs files even though ports
are not allocated. Fetching/reading those files without allocation
of ports leads to crash. Check port allocation before creating
the files.

Change-Id: I85b050a261cca6f961d5d9058efb8b7facf242ce
Signed-off-by: Arumuga Durai A <cadurai@codeaurora.org>
---

diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index bea936a6678b..e0b77946f013 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -1258,6 +1258,9 @@ static ssize_t debug_read_status(struct file *file, char __user *ubuf,
 	int ret;
 	int result = 0;
 
+	if (!ui_dev)
+		return -EINVAL;
+
 	tty = ui_dev->port.tty;
 	gser = ui_dev->port_usb;
 
@@ -1307,6 +1310,9 @@ static ssize_t debug_write_reset(struct file *file, const char __user *buf,
 	struct gs_port *ui_dev = file->private_data;
 	unsigned long flags;
 
+	if (!ui_dev)
+		return -EINVAL;
+
 	spin_lock_irqsave(&ui_dev->port_lock, flags);
 	ui_dev->nbytes_from_host = ui_dev->nbytes_to_tty =
 		ui_dev->nbytes_from_tty = ui_dev->nbytes_to_host = 0;
@@ -1336,6 +1342,9 @@ static void usb_debugfs_init(struct gs_port *ui_dev, int port_num)
 {
 	char buf[48];
 
+	if (!ui_dev)
+		return;
+
 	snprintf(buf, 48, "usb_serial%d", port_num);
 	gs_dent = debugfs_create_dir(buf, 0);
 	if (!gs_dent || IS_ERR(gs_dent))