4.18-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
[ Upstream commit ac63043d8cb5503c7e0fe110f947eacf2663804e ]
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") 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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- 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_ 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_ 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; }