udldrmfb: udl_get_edid: usb_control_msg buffer must not be on the stack

The buffer passed to usb_control_msg may end up in scatter-gather list, and
may thus not be on the stack. Having it on the stack usually works on x86, but
not on other archs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index 3e6208f773e2..353bc1ea6f68 100644
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -22,13 +22,17 @@
 static u8 *udl_get_edid(struct udl_device *udl)
 {
         u8 *block;
-        char rbuf[3];
+        char *rbuf;
         int ret, i;
 
         block = kmalloc(EDID_LENGTH, GFP_KERNEL);
         if (block == NULL)
                 return NULL;
 
+        rbuf = kmalloc(2, GFP_KERNEL);
+        if (rbuf == NULL)
+                goto error;
+
         for (i = 0; i < EDID_LENGTH; i++) {
                 ret = usb_control_msg(udl->ddev->usbdev,
                                       usb_rcvctrlpipe(udl->ddev->usbdev, 0), (0x02),
@@ -42,10 +46,12 @@ static u8 *udl_get_edid(struct udl_device *udl)
                 block[i] = rbuf[1];
         }
 
+        kfree(rbuf);
         return block;
 
 error:
         kfree(block);
+        kfree(rbuf);
         return NULL;
 }