drm/msm: Set drvdata to NULL when msm_drm_init() fails
We should set the platform device's driver data to NULL here so that code doesn't assume the struct drm_device pointer is valid when it could have been destroyed. The lifetime of this pointer is managed by a kref but when msm_drm_init() fails we call drm_dev_put() on the pointer which will free the pointer's memory. This driver uses the component model, so there's sort of two "probes" in this file, one for the platform device i.e. msm_pdev_probe() and one for the component i.e. msm_drm_bind(). The msm_drm_bind() code is using the platform device's driver data to store struct drm_device so the two functions are intertwined. This relationship becomes a problem for msm_pdev_shutdown() when it tests the NULL-ness of the pointer to see if it should call drm_atomic_helper_shutdown(). The NULL test is a proxy check for if the pointer has been freed by kref_put(). If the drm_device has been destroyed, then we shouldn't call the shutdown helper, and we know that is the case if msm_drm_init() failed, therefore set the driver data to NULL so that this pointer liveness is tracked properly. Fixes: 9d5cbf5f ("drm/msm: add shutdown support for display platform_driver") Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Cc: Fabio Estevam <festevam@gmail.com> Cc: Krishna Manikandan <mkrishn@codeaurora.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> Message-Id: <20210325212822.3663144-1-swboyd@chromium.org> Signed-off-by: Rob Clark <robdclark@chromium.org>
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