drm: hdlcd: Unwind the DRM setup on error conditions in the right order.

Message ID 1465390613-15905-1-git-send-email-Liviu.Dudau@arm.com
State New
Headers show

Commit Message

Liviu Dudau June 8, 2016, 12:56 p.m.
In hdlcd_drm_bind()/hdlcd_drm_unbind() we unwind the DRM setup in the
wrong order (drm_mode_config_cleanup() before connector and encoder
had a chance to cleanup their memory or before drm_dev_unregister()).
The correct order should match in both functions.

Reported-by: Robin Murphy <Robin.Murphy@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
---

Robin,

I believe this should fix your problems with HDLCD failing to allocate CMA
memory and then crashing.

Best regards,
Liviu

 drivers/gpu/drm/arm/hdlcd_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Liviu Dudau June 13, 2016, 1:03 p.m. | #1
On Mon, Jun 13, 2016 at 12:02:31PM +0100, Robin Murphy wrote:
> On 08/06/16 13:56, Liviu Dudau wrote:
> >In hdlcd_drm_bind()/hdlcd_drm_unbind() we unwind the DRM setup in the
> >wrong order (drm_mode_config_cleanup() before connector and encoder
> >had a chance to cleanup their memory or before drm_dev_unregister()).
> >The correct order should match in both functions.
> >
> >Reported-by: Robin Murphy <Robin.Murphy@arm.com>
> >Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> >---
> >
> >Robin,
> >
> >I believe this should fix your problems with HDLCD failing to allocate CMA
> >memory and then crashing.
> 
> Heh, I'm not sure I'd even clocked that there was yet another propblem
> beyond the original gem_free_object() crash. I've just tried 4.7-rc3 with
> the relevant fixes for that, and indeed drm_connector_cleanup() does go
> bang, and this patch makes it happy again.
> 
> Tested-by: Robin Murphy <robin.murphy@arm.com>

Cheers! I will push it for the next -rc.

Best regards,
Liviu

> 
> Thanks,
> Robin.
> 
> >
> >Best regards,
> >Liviu
> >
> >  drivers/gpu/drm/arm/hdlcd_drv.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
> >index 3422ca2..2c6eddb 100644
> >--- a/drivers/gpu/drm/arm/hdlcd_drv.c
> >+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
> >@@ -382,7 +382,6 @@ static int hdlcd_drm_bind(struct device *dev)
> >
> >  err_fbdev:
> >  	drm_kms_helper_poll_fini(drm);
> >-	drm_mode_config_cleanup(drm);
> >  	drm_vblank_cleanup(drm);
> >  err_vblank:
> >  	pm_runtime_disable(drm->dev);
> >@@ -390,6 +389,7 @@ err_pm_active:
> >  	component_unbind_all(dev, drm);
> >  err_unregister:
> >  	drm_dev_unregister(drm);
> >+	drm_mode_config_cleanup(drm);
> >  err_unload:
> >  	drm_irq_uninstall(drm);
> >  	of_reserved_mem_device_release(drm->dev);
> >@@ -410,15 +410,15 @@ static void hdlcd_drm_unbind(struct device *dev)
> >  		hdlcd->fbdev = NULL;
> >  	}
> >  	drm_kms_helper_poll_fini(drm);
> >-	component_unbind_all(dev, drm);
> >  	drm_vblank_cleanup(drm);
> >+	component_unbind_all(dev, drm);
> >  	pm_runtime_get_sync(drm->dev);
> >  	drm_irq_uninstall(drm);
> >  	pm_runtime_put_sync(drm->dev);
> >  	pm_runtime_disable(drm->dev);
> >-	of_reserved_mem_device_release(drm->dev);
> >-	drm_mode_config_cleanup(drm);
> >  	drm_dev_unregister(drm);
> >+	drm_mode_config_cleanup(drm);
> >+	of_reserved_mem_device_release(drm->dev);
> >  	drm_dev_unref(drm);
> >  	drm->dev_private = NULL;
> >  	dev_set_drvdata(dev, NULL);
> >
>

Patch

diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
index 3422ca2..2c6eddb 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.c
+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
@@ -382,7 +382,6 @@  static int hdlcd_drm_bind(struct device *dev)
 
 err_fbdev:
 	drm_kms_helper_poll_fini(drm);
-	drm_mode_config_cleanup(drm);
 	drm_vblank_cleanup(drm);
 err_vblank:
 	pm_runtime_disable(drm->dev);
@@ -390,6 +389,7 @@  err_pm_active:
 	component_unbind_all(dev, drm);
 err_unregister:
 	drm_dev_unregister(drm);
+	drm_mode_config_cleanup(drm);
 err_unload:
 	drm_irq_uninstall(drm);
 	of_reserved_mem_device_release(drm->dev);
@@ -410,15 +410,15 @@  static void hdlcd_drm_unbind(struct device *dev)
 		hdlcd->fbdev = NULL;
 	}
 	drm_kms_helper_poll_fini(drm);
-	component_unbind_all(dev, drm);
 	drm_vblank_cleanup(drm);
+	component_unbind_all(dev, drm);
 	pm_runtime_get_sync(drm->dev);
 	drm_irq_uninstall(drm);
 	pm_runtime_put_sync(drm->dev);
 	pm_runtime_disable(drm->dev);
-	of_reserved_mem_device_release(drm->dev);
-	drm_mode_config_cleanup(drm);
 	drm_dev_unregister(drm);
+	drm_mode_config_cleanup(drm);
+	of_reserved_mem_device_release(drm->dev);
 	drm_dev_unref(drm);
 	drm->dev_private = NULL;
 	dev_set_drvdata(dev, NULL);