[PATCH] udlfb: fix NULL pointer dereference in dlfb_usb_probe()

From: Alexey Khoroshilov
Date: Fri Nov 09 2018 - 15:25:25 EST


If memory allocation for dlfb fails, error handling code
unconditionally dereference NULL pointer.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Fixes: 68a958a915ca ("udlfb: handle unplug properly")
---
drivers/video/fbdev/udlfb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index 070026a7e55a..9643fe7c8349 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1590,7 +1590,7 @@ static int dlfb_usb_probe(struct usb_interface *intf,
int i;
const struct device_attribute *attr;
struct dlfb_data *dlfb;
- struct fb_info *info;
+ struct fb_info *info = NULL;
int retval = -ENOMEM;
struct usb_device *usbdev = interface_to_usbdev(intf);

@@ -1701,8 +1701,8 @@ static int dlfb_usb_probe(struct usb_interface *intf,
return 0;

error:
- if (dlfb->info) {
- dlfb_ops_destroy(dlfb->info);
+ if (info) {
+ dlfb_ops_destroy(info);
} else if (dlfb) {
usb_put_dev(dlfb->udev);
kfree(dlfb);
--
2.7.4