drm/rockchip: cancel pending vblanks on close
When closing the DRM device while a vblank is pending, we access
file_priv after it has been free'd, which gives:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
PC is at __list_add+0x5c/0xe8
LR is at send_vblank_event+0x54/0x1f0
...
[<c02952e8>] (__list_add) from [<c031a7b4>] (send_vblank_event+0x54/0x1f0)
[<c031a760>] (send_vblank_event) from [<c031a9c0>] (drm_send_vblank_event+0x70/0x78)
[<c031a950>] (drm_send_vblank_event) from [<c031a9f8>] (drm_crtc_send_vblank_event+0x30/0x34)
[<c031a9c8>] (drm_crtc_send_vblank_event) from [<c0339ad8>] (vop_isr+0x224/0x28c)
[<c03398b4>] (vop_isr) from [<c0081780>] (handle_irq_event_percpu+0x12c/0x3e4)
This can be triggered somewhat reliably with:
modetest -M rockchip -v -s ...
Add a preclose hook to the driver so that we can discard any pending
vblank events when the device is closed.
Signed-off-by: John Keeping <john@metanate.com>
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index 896da09..f556a8f 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -251,6 +251,27 @@
return 0;
}
+static void rockchip_drm_crtc_cancel_pending_vblank(struct drm_crtc *crtc,
+ struct drm_file *file_priv)
+{
+ struct rockchip_drm_private *priv = crtc->dev->dev_private;
+ int pipe = drm_crtc_index(crtc);
+
+ if (pipe < ROCKCHIP_MAX_CRTC &&
+ priv->crtc_funcs[pipe] &&
+ priv->crtc_funcs[pipe]->cancel_pending_vblank)
+ priv->crtc_funcs[pipe]->cancel_pending_vblank(crtc, file_priv);
+}
+
+static void rockchip_drm_preclose(struct drm_device *dev,
+ struct drm_file *file_priv)
+{
+ struct drm_crtc *crtc;
+
+ list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+ rockchip_drm_crtc_cancel_pending_vblank(crtc, file_priv);
+}
+
void rockchip_drm_lastclose(struct drm_device *dev)
{
struct rockchip_drm_private *priv = dev->dev_private;
@@ -281,6 +302,7 @@
DRIVER_PRIME | DRIVER_ATOMIC,
.load = rockchip_drm_load,
.unload = rockchip_drm_unload,
+ .preclose = rockchip_drm_preclose,
.lastclose = rockchip_drm_lastclose,
.get_vblank_counter = drm_vblank_no_hw_counter,
.enable_vblank = rockchip_drm_crtc_enable_vblank,