[PATCH] net: macb: fix ref count leaking via pm_runtime_get_sync

[PATCH] net: macb: fix ref count leaking via pm_runtime_get_sync

[Navid Emamdoost]

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@gmail.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

Re: [PATCH] net: macb: fix ref count leaking via pm_runtime_get_sync

[David Miller]

From: Navid Emamdoost <navid.emamdoost@gmail.com>
Date: Sun, 14 Jun 2020 00:48:03 -0500

> 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@gmail.com>

This does not apply to the net tree.

Re: [PATCH] net: macb: fix ref count leaking via pm_runtime_get_sync

[Markus Elfring]

> in macb_mdio_write, …

* Will a desire evolve to improve also this commit message?

* Will the tag “Fixes” become helpful?


…
> +++ b/drivers/net/ethernet/cadence/macb_main.c
…
> @@ -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;
>  }
…

Perhaps use the label “put_runtime” instead?

Regards,
Markus