From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH 3/9] drm/msm: fix OF child-node lookup Date: Wed, 22 Aug 2018 09:41:04 -0500 Message-ID: References: <20180822105547.9634-1-johan@kernel.org> <20180822105547.9634-4-johan@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20180822105547.9634-4-johan@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Johan Hovold Cc: Greg Kroah-Hartman , Frank Rowand , devicetree@vger.kernel.org, "linux-kernel@vger.kernel.org" , stable , Jordan Crouse , Rob Clark , David Airlie List-Id: devicetree@vger.kernel.org On Wed, Aug 22, 2018 at 5:57 AM Johan Hovold wrote: > > 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 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 # 4.12 > Cc: Jordan Crouse > Cc: Rob Clark > Cc: David Airlie > Signed-off-by: Johan Hovold > --- > 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"); Not really your problem, but this is undocumented and a downstream binding. There's been OPP support in addition for more than a year now, we should just remove this code IMO. For some reason though, no one updated the 8064 dts though. Rob