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net: stmmac: dwmac-sun8i: fix OF child-node lookup

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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: 634db83b82 ("net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs")
Tested-by: 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>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Johan Hovold 2018-08-27 10:21:51 +02:00 committed by Rob Herring
parent d397dbe606
commit ac63043d8c
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
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@ -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;
}