From: fuyufan fuyufan@huawei.com
we get (Unable to handle kernel NULL pointer dereference at virtual address 000000000000000c) when call drm_property_blob_put(). After analysis, we get the following process:
alloc faild: drm_atomic_set_mode_for_crtc() drm_property_create_blob() // failed state->mode_blob = ERR_PTR(-ENOMEM)
free illegal pointer: __drm_atomic_helper_crtc_destroy_state() drm_property_blob_put(state->mode_blob) drm_mode_object_put(&blob->base); // here blob is ERR_PTR(-ENOMEM)
So do we have to determine if blob is an error code before calling drm_mode_object_put().
Signed-off-by: fuyufan fuyufan@huawei.com --- drivers/gpu/drm/drm_property.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c index 69dfed57c..05dba22fe 100644 --- a/drivers/gpu/drm/drm_property.c +++ b/drivers/gpu/drm/drm_property.c @@ -597,7 +597,7 @@ EXPORT_SYMBOL(drm_property_create_blob); */ void drm_property_blob_put(struct drm_property_blob *blob) { - if (!blob) + if (IS_ERR_OR_NULL(blob)) return;
drm_mode_object_put(&blob->base); -- 2.23.0