drm_hwcomposer: Initialize buffer_ pointer to NULL
In some cases, we've seen drm_hwcomposer start to try to
compose frames before anything has called SetClientTarget().
This seems to be some sort of a race, which for some reason
we only see with certain dummy HDMI dongles (which provide
fake EDID data) which allow our lab machines to run headless.
I'm still trying to understand more about why this happens
only in this case.
The net of the issue is we see CreateComposition() being called,
which adds the client_layer_ to the zmap. Then it creates the
DrmHwcLayers copying the non-initialized buffer_ value as the
sf_handle.
This then later causes a crash in ImportBuffer() when we
traverse the non-null (but invalid) hnd value.
Thus, this patch simply initilizes the buffer_ pointer to NULL
so that we error out properly in the case of the race.
Reported-by: YongQin Liu <yongqin.liu@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I5fde3fccde86519edb04e61cbc2842eda395ade4
diff --git a/drmhwctwo.h b/drmhwctwo.h
index fd14b1f..d9ced9b 100644
--- a/drmhwctwo.h
+++ b/drmhwctwo.h
@@ -111,7 +111,7 @@
HWC2::Composition validated_type_ = HWC2::Composition::Invalid;
HWC2::BlendMode blending_ = HWC2::BlendMode::None;
- buffer_handle_t buffer_;
+ buffer_handle_t buffer_ = NULL;
UniqueFd acquire_fence_;
int release_fence_raw_ = -1;
UniqueFd release_fence_;