Use the new of_get_compatible_child() helper to lookup the legacy pwrlevels child node instead of using of_find_compatible_node(), which searches the entire tree from a given start node and thus can return an unrelated (i.e. non-child) node.

This also addresses a potential use-after-free (e.g. after probe deferral) as the tree-wide helper drops a reference to its first argument (i.e. the probed device's node).

While at it, also fix the related child-node reference leak.

Fixes: e2af8b6b0ca1 ("drm/msm: gpu: Use OPP tables if we can") Cc: stable stable@vger.kernel.org # 4.12 Cc: Jordan Crouse jcrouse@codeaurora.org Cc: Rob Clark robdclark@gmail.com Cc: David Airlie airlied@linux.ie Signed-off-by: Johan Hovold johan@kernel.org --- drivers/gpu/drm/msm/adreno/adreno_gpu.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c index da1363a0c54d..93d70f4a2154 100644 --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c @@ -633,8 +633,7 @@ static int adreno_get_legacy_pwrlevels(struct device *dev) struct device_node *child, *node; int ret;

- node = of_find_compatible_node(dev->of_node, NULL, - "qcom,gpu-pwrlevels"); + node = of_get_compatible_child(dev->of_node, "qcom,gpu-pwrlevels"); if (!node) { dev_err(dev, "Could not find the GPU powerlevels\n"); return -ENXIO; @@ -655,6 +654,8 @@ static int adreno_get_legacy_pwrlevels(struct device *dev) dev_pm_opp_add(dev, val, 0); }

+ of_node_put(node); + return 0; }