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From: Johan Hovold <johan@kernel.org>
To: Rob Herring <robh+dt@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan@kernel.org>,
	Corentin Labbe <clabbe.montjoie@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S . Miller" <davem@davemloft.net>
Subject: [PATCH 7/9] net: stmmac: dwmac-sun8i: fix OF child-node lookup
Date: Wed, 22 Aug 2018 12:55:45 +0200	[thread overview]
Message-ID: <20180822105547.9634-8-johan@kernel.org> (raw)
In-Reply-To: <20180822105547.9634-1-johan@kernel.org>

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 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


  parent reply	other threads:[~2018-08-22 10:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-22 10:55 [PATCH 0/9] of: fix compatible-child-node lookups Johan Hovold
2018-08-22 10:55 ` [PATCH 1/9] of: add helper to lookup compatible child node Johan Hovold
2018-08-23  3:17   ` kbuild test robot
2018-08-23  7:39     ` Johan Hovold
2018-08-22 10:55 ` [PATCH 2/9] drm/mediatek: fix OF sibling-node lookup Johan Hovold
2018-08-22 10:55 ` [PATCH 3/9] drm/msm: fix OF child-node lookup Johan Hovold
2018-08-22 14:41   ` Rob Herring
2018-08-22 10:55 ` [PATCH 4/9] mmc: meson-mx-sdio: " Johan Hovold
2018-08-23 18:50   ` Martin Blumenstingl
2018-08-24  6:41     ` Johan Hovold
2018-08-22 10:55 ` [PATCH 5/9] mtd: nand: atmel: " Johan Hovold
2018-08-22 10:55 ` [PATCH 6/9] net: bcmgenet: " Johan Hovold
2018-08-22 10:55 ` Johan Hovold [this message]
2018-08-22 10:55 ` [PATCH 8/9] NFC: nfcmrvl_uart: " Johan Hovold
2018-08-22 10:55 ` [PATCH 9/9] power: supply: twl4030-charger: fix OF sibling-node lookup Johan Hovold
2018-08-22 21:36   ` Sebastian Reichel
2018-08-23  7:40     ` Johan Hovold
2018-08-22 14:32 ` [PATCH 0/9] of: fix compatible-child-node lookups Rob Herring
2018-08-22 14:46   ` Johan Hovold

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