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

commit 8dbc2ccac5a65c5b57e3070e36a3dc97c7970d96 upstream.

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@vger.kernel.org # 3.13+
Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 99ee60f..8c0a572 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -512,6 +512,7 @@ static int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file
                        *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: