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

From: Alexey Khoroshilov <khoroshilov@ispras.ru>
To: Mikulas Patocka <mpatocka@redhat.com>,
	Bernie Thompson <bernie@plugable.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>,
	linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org
Subject: [PATCH] udlfb: fix NULL pointer dereference in dlfb_usb_probe()
Date: Fri,  9 Nov 2018 23:25:10 +0300	[thread overview]
Message-ID: <1541795110-3179-1-git-send-email-khoroshilov@ispras.ru> (raw)

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@ispras.ru>
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

