Il 19/09/23 03:45, Ying Liu ha scritto:
Hi Angelo,
Thank you for the patch.
On Monday, September 18, 2023 11:01 PM, AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
When external bridges are attached with
DRM_BRIDGE_ATTACH_NO_CONNECTOR,
the panel bridge may also get the same flag, but in the .attach()
callback for the panel bridge a device link is added only when this
flag is not present; To make things worse, the .detach() callback
tries to delete the device link unconditionally and without checking
if it was created in the first place, crashing the kernel with a NULL
pointer kernel panic upon calling panel_bridge_detach().
Fix that by moving the device_link_add() call before checking if the
DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is present.
Fixes: 199cf07ebd2b ("drm/bridge: panel: Add a device link between drm
device and panel device")
Signed-off-by: AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/gpu/drm/bridge/panel.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/bridge/panel.c
b/drivers/gpu/drm/bridge/panel.c
index e00d2e94c751..8c507dfd589e 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -67,14 +67,6 @@ static int panel_bridge_attach(struct drm_bridge
*bridge,
struct drm_device *drm_dev = bridge->dev;
int ret;
- if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
- return 0;
-
- if (!bridge->encoder) {
- DRM_ERROR("Missing encoder\n");
- return -ENODEV;
- }
-
panel_bridge->link = device_link_add(drm_dev->dev, panel->dev,
DL_FLAG_STATELESS);
if (!panel_bridge->link) {
@@ -83,6 +75,14 @@ static int panel_bridge_attach(struct drm_bridge
*bridge,
return -EINVAL;
}
+ if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
+ return 0;
+
+ if (!bridge->encoder) {
+ DRM_ERROR("Missing encoder\n");
Shouldn't the device link be deleted in case of error?
Whoops! Yes, that's right. I'm sending a v2 right now.
Thanks!
Angelo
Regards,
Liu Ying
+ return -ENODEV;
+ }
+
drm_connector_helper_add(connector,
&panel_bridge_connector_helper_funcs);
--
2.42.0
