[PATCH] drm/radeon: fix copy of uninitialized variable back to userspace

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
copy back uninitialised data in value_tmp that pointer *value points
to. This can occur when rdev->family is less than CHIP_BONAIRE and
less than CHIP_TAHITI.  Fix this by adding in a missing -EINVAL
so that no invalid value is copied back to userspace.

Addresses-Coverity: ("Uninitialized scalar variable)
Cc: stable at vger.kernel.org # 3.13+
Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 drivers/gpu/drm/radeon/radeon_kms.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 2479d6ab7a36..58876bb4ef2a 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -518,6 +518,7 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 			*value = rdev->config.si.backend_enable_mask;
 		} else {
 			DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
+			return -EINVAL;
 		}
 		break;
 	case RADEON_INFO_MAX_SCLK:
-- 
2.30.0