drm/msm: fix NULL-deref on irq uninstall

commit cd459c005de3e2b855a8cc7768e633ce9d018e9f upstream.

In case of early initialisation errors and on platforms that do not use
the DPU controller, the deinitilisation code can be called with the kms
pointer set to NULL.

Fixes: f026e431cf86 ("drm/msm: Convert to Linux IRQ interfaces")
Cc: stable@vger.kernel.org	# 5.14
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/525104/
Link: https://lore.kernel.org/r/20230306100722.28485-5-johan+linaro@kernel.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 91609e86c9aa4e66e4b21aca079191a014339b10..e238d2beb7abe3d4f595b2ca329f3c69a10ed434 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -364,9 +364,11 @@ static int msm_drm_uninit(struct device *dev)
 
        drm_mode_config_cleanup(ddev);
 
-       pm_runtime_get_sync(dev);
-       msm_irq_uninstall(ddev);
-       pm_runtime_put_sync(dev);
+       if (kms) {
+               pm_runtime_get_sync(dev);
+               msm_irq_uninstall(ddev);
+               pm_runtime_put_sync(dev);
+       }
 
        if (kms && kms->funcs)
                kms->funcs->destroy(kms);