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SubjectRe: [PATCH] iommu/mediatek: fix leaked of_node references
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On 17/04/2019 04:41, Wen Yang wrote:
> The call to of_parse_phandle returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
>
> 581 static int mtk_iommu_probe(struct platform_device *pdev)
> 582 {
> ...
> 626 for (i = 0; i < larb_nr; i++) {
> 627 struct device_node *larbnode;
> ...
> 631 larbnode = of_parse_phandle(...);
> 632 if (!larbnode)
> 633 return -EINVAL;
> 634
> 635 if (!of_device_is_available(larbnode))
> 636 continue; ---> leaked here
> 637
> ...
> 643 if (!plarbdev)
> 644 return -EPROBE_DEFER; ---> leaked here
> ...
> 647 component_match_add_release(dev, &match, release_of,
> 648 compare_of, larbnode);
> ---> release_of will call of_node_put
> 649 }
> ...
> 650
>
> Detected by coccinelle with the following warnings:
> ./drivers/iommu/mtk_iommu.c:644:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 631, but without a corresponding object release within this function.
>
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: iommu@lists.linux-foundation.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mediatek@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org

Reviewed-by: Matthias Brugger <mbrugger@suse.com>

> ---
> drivers/iommu/mtk_iommu.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index de3e022..b66d11b 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -632,16 +632,20 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> if (!larbnode)
> return -EINVAL;
>
> - if (!of_device_is_available(larbnode))
> + if (!of_device_is_available(larbnode)) {
> + of_node_put(larbnode);
> continue;
> + }
>
> ret = of_property_read_u32(larbnode, "mediatek,larb-id", &id);
> if (ret)/* The id is consecutive if there is no this property */
> id = i;
>
> plarbdev = of_find_device_by_node(larbnode);
> - if (!plarbdev)
> + if (!plarbdev) {
> + of_node_put(larbnode);
> return -EPROBE_DEFER;
> + }
> data->smi_imu.larb_imu[id].dev = &plarbdev->dev;
>
> component_match_add_release(dev, &match, release_of,
>

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