From: Johan Hovold <johan@kernel.org>
Date: Mon, 27 Aug 2018 10:21:47 +0200
Subject: drm/msm: fix OF child-node lookup
Git-commit: f9a7082327e26f54067a49cac2316d31e0cc8ba7
Patch-mainline: v4.20-rc1
References: bsc#1106110
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.
Backporting notes:
* apply changes in adreno_device.c
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>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/msm/adreno/adreno_device.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -220,8 +220,7 @@ static int adreno_get_legacy_pwrlevels(s
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;
@@ -242,6 +241,8 @@ static int adreno_get_legacy_pwrlevels(s
dev_pm_opp_add(dev, val, 0);
}
+ of_node_put(node);
+
return 0;
}