[PATCH AUTOSEL 5.17 42/60] drm/radeon: fix a possible null pointer dereference

Sasha Levin
2022-06-07T19:18:07Z

From: Gong Yuanjun <ruc_gongyuanjun@163.com>

[ Upstream commit a2b28708b645c5632dc93669ab06e97874c8244f ]

In radeon_fp_native_mode(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference
on failure of drm_mode_duplicate(). Add a check to avoid npd.

The failure status of drm_cvt_mode() on the other path is checked too.

Signed-off-by: Gong Yuanjun <ruc_gongyuanjun@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/radeon/radeon_connectors.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 1546abcadacf..d157bb9072e8 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -473,6 +473,8 @@ static struct drm_display_mode *radeon_fp_native_mode(struct drm_encoder *encode
native_mode->vdisplay != 0 &&
native_mode->clock != 0) {
mode = drm_mode_duplicate(dev, native_mode);
+ if (!mode)
+ return NULL;
mode->type = DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER;
drm_mode_set_name(mode);

@@ -487,6 +489,8 @@ static struct drm_display_mode *radeon_fp_native_mode(struct drm_encoder *encode
* simpler.
*/
mode = drm_cvt_mode(dev, native_mode->hdisplay, native_mode->vdisplay, 60, true, false, false);
+ if (!mode)
+ return NULL;
mode->type = DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER;
DRM_DEBUG_KMS("Adding cvt approximation of native panel mode %s\n", mode->name);
}
--
2.35.1