FB/S3C2410: check default_display parameter passed in platform data

Ensure that the default display parameter passed in via the
device's platform data is valid. It turns out when mach-bast.c
was updated, the default_display was set outside of the display
array bounds, causing a panic on startup.

If the default_display is bigger than num_displays, then generate
an error and refuse to initialise the driver.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/video/s3c2410fb.c b/drivers/video/s3c2410fb.c
index e63f536e9fed..71fa6edb5c47 100644
--- a/drivers/video/s3c2410fb.c
+++ b/drivers/video/s3c2410fb.c
@@ -817,6 +817,12 @@ static int __init s3c24xxfb_probe(struct platform_device *pdev,
                 return -EINVAL;
         }
 
+        if (mach_info->default_display >= mach_info->num_displays) {
+                dev_err(&pdev->dev, "default is %d but only %d displays\n",
+                        mach_info->default_display, mach_info->num_displays);
+                return -EINVAL;
+        }
+
         display = mach_info->displays + mach_info->default_display;
 
         irq = platform_get_irq(pdev, 0);