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    SubjectRe: [PATCH v2 7/9] net: stmmac: dwmac-sun8i: fix OF child-node lookup
    On Mon, Aug 27, 2018 at 10:21:51AM +0200, Johan Hovold wrote:
    > Use the new of_get_compatible_child() helper to lookup the mdio-internal
    > 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 mdio-mux node). Fortunately, this was inadvertently
    > balanced by a failure to drop the mdio-mux reference after lookup.
    >
    > While at it, also fix the related mdio-internal- and phy-node reference
    > leaks.
    >
    > Fixes: 634db83b8265 ("net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs")
    > Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
    > Cc: Andrew Lunn <andrew@lunn.ch>
    > Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
    > Cc: Alexandre Torgue <alexandre.torgue@st.com>
    > Cc: Jose Abreu <joabreu@synopsys.com>
    > Cc: David S. Miller <davem@davemloft.net>
    > Signed-off-by: Johan Hovold <johan@kernel.org>
    > ---
    > drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 12 ++++++++++--
    > 1 file changed, 10 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
    > index f9a61f90cfbc..0f660af01a4b 100644
    > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
    > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
    > @@ -714,8 +714,9 @@ static int get_ephy_nodes(struct stmmac_priv *priv)
    > return -ENODEV;
    > }
    >
    > - mdio_internal = of_find_compatible_node(mdio_mux, NULL,
    > + mdio_internal = of_get_compatible_child(mdio_mux,
    > "allwinner,sun8i-h3-mdio-internal");
    > + of_node_put(mdio_mux);
    > if (!mdio_internal) {
    > dev_err(priv->device, "Cannot get internal_mdio node\n");
    > return -ENODEV;
    > @@ -729,13 +730,20 @@ static int get_ephy_nodes(struct stmmac_priv *priv)
    > gmac->rst_ephy = of_reset_control_get_exclusive(iphynode, NULL);
    > if (IS_ERR(gmac->rst_ephy)) {
    > ret = PTR_ERR(gmac->rst_ephy);
    > - if (ret == -EPROBE_DEFER)
    > + if (ret == -EPROBE_DEFER) {
    > + of_node_put(iphynode);
    > + of_node_put(mdio_internal);
    > return ret;
    > + }
    > continue;
    > }
    > dev_info(priv->device, "Found internal PHY node\n");
    > + of_node_put(iphynode);
    > + of_node_put(mdio_internal);
    > return 0;
    > }
    > +
    > + of_node_put(mdio_internal);
    > return -ENODEV;
    > }
    >
    > --
    > 2.18.0
    >

    Sorry for the delay
    Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>

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