[PATCH] udlfb: don't call unregister_framebuffer on a null pointer

DORMANTno replies

From: Colin King <hidden>
Date: 2018-11-24 14:48:45
Also in: dri-devel, kernel-janitors, lkml
Subsystem: displaylink usb 2.0 framebuffer driver (udlfb), framebuffer layer, the rest · Maintainers: Bernie Thompson, Helge Deller, Linus Torvalds

From: Colin Ian King <redacted>

Just before calling unregister_framebuffer with info there is a
null check on info, implying info may possibly zero.  Calling
unregister_framebuffer with a null pointer will cause a null
pointer dereference, fix this by moving the call to the block
where info has been null checked.

Detected by CoverityScan, CID#1473969 ("Dereference after null check")

Fixes: 68a958a915ca ("udlfb: handle unplug properly")
Signed-off-by: Colin Ian King <redacted>
---
 drivers/video/fbdev/udlfb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index 070026a7e55a..cf8597f43d7e 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1735,9 +1735,9 @@ static void dlfb_usb_disconnect(struct usb_interface *intf)
 		for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
 			device_remove_file(info->dev, &fb_device_attrs[i]);
 		device_remove_bin_file(info->dev, &edid_attr);
+		unregister_framebuffer(info);
 	}
 
-	unregister_framebuffer(info);
 }
 
 static struct usb_driver dlfb_driver = {
-- 
2.19.1
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help