Hi Sean,
On 04/11/2017 04:31 AM, Sean Paul wrote:
On Mon, Apr 10, 2017 at 06:00:45PM +0800, Jeffy Chen wrote:
After unbinding drm, the user space may still owns the drm dev fd,
and may trigger fb release after cleanup mode config.
Add a sanity check to prevent that.
Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
---
Changes in v6: None
Changes in v5: None
Changes in v2: None
drivers/gpu/drm/drm_framebuffer.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index e8f9c13..03c1632 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -583,6 +583,11 @@ void drm_fb_release(struct drm_file *priv)
{
struct drm_framebuffer *fb, *tfb;
struct drm_mode_rmfb_work arg;
+ struct drm_minor *minor = priv->minor;
+ struct drm_device *dev = minor->dev;
+
+ if (WARN_ON(!dev->mode_config.num_fb && !list_empty(&priv->fbs)))
Have you actually seen this happen? num_fb should be tightly couple to
priv->fbs, so it seems like this could only result from a driver bug (or I'm not
reading the code correctly).
yes, 100% repro by:
1/ start display server
2/ unbind drm
3/ stop display server
the num_fb would be decreased(with a warning in
drm_mode_config_cleanup's fb_list check) in
drm_mode_config_cleanup->drm_framebuffer_free->rockchip_drm_fb_destroy->drm_framebuffer_cleanup
this flow would not modify the priv->fbs at the same time. so it would
still remains the pointer of those freed fb.
Sean
+ return;
INIT_LIST_HEAD(&arg.fbs);
--
2.1.4
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