linux-kernel - [PATCH] net: macb: fix ref count leaking via pm_runtime_get

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Date:   Sun, 14 Jun 2020 00:48:03 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     Nicolas Ferre <nicolas.ferre@...rochip.com>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     emamd001@....edu, wu000273@....edu, kjlu@....edu, smccaman@....edu,
        Navid Emamdoost <navid.emamdoost@...il.com>
Subject: [PATCH] net: macb: fix ref count leaking via pm_runtime_get_sync

in macb_mdio_write, macb_mdio_read, and at91ether_open,
pm_runtime_get_sync is called which increments the counter even in case of
failure, leading to incorrect ref count.
In case of failure, decrement the ref count before returning.

Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index a0e8c5bbabc0..3646ab5a1e83 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -335,7 +335,7 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 
 	status = pm_runtime_get_sync(&bp->pdev->dev);
 	if (status < 0)
-		goto mdio_pm_exit;
+		goto mdio_pm_put;
 
 	status = macb_mdio_wait_for_idle(bp);
 	if (status < 0)
@@ -374,6 +374,7 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 
 mdio_read_exit:
 	pm_runtime_mark_last_busy(&bp->pdev->dev);
+mdio_pm_put:
 	pm_runtime_put_autosuspend(&bp->pdev->dev);
 mdio_pm_exit:
 	return status;
@@ -387,7 +388,7 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 
 	status = pm_runtime_get_sync(&bp->pdev->dev);
 	if (status < 0)
-		goto mdio_pm_exit;
+		goto mdio_pm_put;
 
 	status = macb_mdio_wait_for_idle(bp);
 	if (status < 0)
@@ -426,6 +427,7 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 
 mdio_write_exit:
 	pm_runtime_mark_last_busy(&bp->pdev->dev);
+mdio_pm_put:
 	pm_runtime_put_autosuspend(&bp->pdev->dev);
 mdio_pm_exit:
 	return status;
@@ -3817,7 +3819,7 @@ static int at91ether_open(struct net_device *dev)
 
 	ret = pm_runtime_get_sync(&lp->pdev->dev);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	/* Clear internal statistics */
 	ctl = macb_readl(lp, NCR);
@@ -3827,7 +3829,7 @@ static int at91ether_open(struct net_device *dev)
 
 	ret = at91ether_start(dev);
 	if (ret)
-		return ret;
+		goto out;
 
 	/* Enable MAC interrupts */
 	macb_writel(lp, IER, MACB_BIT(RCOMP)	|
@@ -3840,11 +3842,14 @@ static int at91ether_open(struct net_device *dev)
 
 	ret = macb_phylink_connect(lp);
 	if (ret)
-		return ret;
+		goto out;
 
 	netif_start_queue(dev);
 
 	return 0;
+out:
+	pm_runtime_put(&lp->pdev->dev);
+	return ret;
 }
 
 /* Close the interface */
-- 
2.17.1