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From a63c863e6d1fac6e8e93f3a72df649cd5655e6e3 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Tue, 17 Sep 2019 14:09:35 +0200
Subject: [PATCH 3963/4256] drm/kms: Duct-tape for mode object lifetime checks
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commit 4f5368b5541a902f6596558b05f5c21a9770dd32
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Fri Jun 14 08:17:23 2019 +0200
drm/kms: Catch mode_object lifetime errors
uncovered a bit a mess in dp drivers. Most drivers (from a quick look,
all except i915) register all the dp stuff in their init code, which
is too early. With CONFIG_DRM_DP_AUX_CHARDEV this will blow up,
because drm_dp_aux_register tries to add a child to a device in sysfs
(the connector) which doesn't even exist yet.
No one seems to have cared thus far. But with the above change I also
moved the setting of dev->registered after the ->load callback, in an
attempt to keep old drivers from hitting any WARN_ON backtraces. But
that moved radeon.ko from the "working, by accident" to "now also
broken" category.
Since this is a huge mess I figured a revert would be simplest. But
this check has already caught issues in i915:
commit 1b9bd09630d4db4827cc04d358a41a16a6bc2cb0
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Tue Aug 20 19:16:57 2019 +0300
drm/i915: Do not create a new max_bpc prop for MST connectors
Hence I'd like to retain it. Fix the radeon regression by moving the
setting of dev->registered back to were it was, and stop the
backtraces with an explicit check for dev->driver->load.
Everyone else will stay as broken with CONFIG_DRM_DP_AUX_CHARDEV. The
next patch will improve the kerneldoc and add a todo entry for this.
Fixes: 4f5368b5541a ("drm/kms: Catch mode_object lifetime errors")
Cc: Sean Paul <sean@poorly.run>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Tested-by: Michel Dänzer <mdaenzer@redhat.com>
Cc: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190917120936.7501-1-daniel.vetter@ffwll.ch
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_mode_object.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index fcb0ab0abb75..126750583415 100644
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -37,6 +37,8 @@ int __drm_mode_object_add(struct drm_device *dev, struct drm_mode_object *obj,
{
int ret;
+ WARN_ON(!dev->driver->load && dev->registered && !obj_free_cb);
+
mutex_lock(&dev->mode_config.idr_mutex);
ret = idr_alloc(&dev->mode_config.crtc_idr, register_obj ? obj : NULL, 1, 0, GFP_KERNEL);
if (ret >= 0) {
@@ -96,6 +98,8 @@ void drm_mode_object_register(struct drm_device *dev,
void drm_mode_object_unregister(struct drm_device *dev,
struct drm_mode_object *object)
{
+ WARN_ON(!dev->driver->load && dev->registered && !object->free_cb);
+
mutex_lock(&dev->mode_config.idr_mutex);
if (object->id) {
idr_remove(&dev->mode_config.crtc_idr, object->id);
--
2.17.1
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