Hi Daniel,
On 04/06/2017 04:26 PM, Daniel Vetter wrote:
On Wed, Apr 05, 2017 at 12:28:40PM -0400, Sean Paul wrote:
On Wed, Apr 05, 2017 at 04:29:26PM +0800, Jeffy Chen wrote:
After unbinding drm, the userspace may still has a chance to access
gem buf.
Add a sanity check for a NULL dev_private to prevent that from
happening.
I still don't understand how this is happening. You're saying that these hooks
can be called after rockchip_drm_unbind() has finished?
Yeah this is supposed to be impossible. If it isn't, we need to debug and
fix this properly. This smells like pretty bad duct-tape ...
it looks like after unbind, the user space may still own drm dev fd, and
could be able to call ioctl:
lrwx------. 1 chronos chronos 64 Mar 15 12:53 28 -> /dev/dri/card1 (deleted)
and the drm_unplug_dev may help it, maybe we should call it in unbind?
or just break drm_ioctl when drm_dev not registered?
-Daniel
Sean
Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
---
Changes in v3:
Address Daniel Vetter <daniel@xxxxxxxx>'s comments.
Update commit message.
Changes in v2: None
drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index df9e570..205a3dc 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -184,6 +184,9 @@ static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
struct drm_device *drm = obj->dev;
struct rockchip_drm_private *private = drm->dev_private;
+ if (!private)
+ return -ENODEV;
+
if (private->domain)
return rockchip_gem_alloc_iommu(rk_obj, alloc_kmap);
else
@@ -208,6 +211,11 @@ static void rockchip_gem_free_dma(struct rockchip_gem_object *rk_obj)
static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
{
+ struct drm_device *drm = rk_obj->base.dev;
+
+ if (!drm->dev_private)
+ return;
+
if (rk_obj->pages)
rockchip_gem_free_iommu(rk_obj);
else
--
2.1.4
--
Sean Paul, Software Engineer, Google / Chromium OS
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