2022-01-10 06:40:45

by Miaoqian Lin

Subject: [PATCH] net: hns: Fix missing put_device() call in hns_mac_register_phy

We need to drop the reference taken by hns_dsaf_find_platform_device
Missing put_device() may cause refcount leak.

Fixes: 804ffe5c6197 ("net: hns: support deferred probe when no mdio")
Signed-off-by: Miaoqian Lin <[email protected]>
---
drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
index 7edf8569514c..7364e05487c7 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
@@ -764,6 +764,7 @@ static int hns_mac_register_phy(struct hns_mac_cb *mac_cb)
dev_err(mac_cb->dev,
"mac%d mdio is NULL, dsaf will probe again later\n",
mac_cb->mac_id);
+ put_device(&pdev->dev);
return -EPROBE_DEFER;
}

--
2.17.1

2022-01-12 04:33:40

by Jakub Kicinski

Subject: Re: [PATCH] net: hns: Fix missing put_device() call in hns_mac_register_phy

On Mon, 10 Jan 2022 06:40:29 +0000 Miaoqian Lin wrote:
> We need to drop the reference taken by hns_dsaf_find_platform_device
> Missing put_device() may cause refcount leak.
>
> Fixes: 804ffe5c6197 ("net: hns: support deferred probe when no mdio")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
> index 7edf8569514c..7364e05487c7 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
> @@ -764,6 +764,7 @@ static int hns_mac_register_phy(struct hns_mac_cb *mac_cb)
> dev_err(mac_cb->dev,
> "mac%d mdio is NULL, dsaf will probe again later\n",
> mac_cb->mac_id);
> + put_device(&pdev->dev);
> return -EPROBE_DEFER;
> }
>

With more context:

@@ -755,24 +755,25 @@ static int hns_mac_register_phy(struct hns_mac_cb *mac_cb)
pdev = hns_dsaf_find_platform_device(args.fwnode);
if (!pdev) {
dev_err(mac_cb->dev, "mac%d mdio pdev is NULL\n",
mac_cb->mac_id);
return -EINVAL;
}

mii_bus = platform_get_drvdata(pdev);
if (!mii_bus) {
dev_err(mac_cb->dev,
"mac%d mdio is NULL, dsaf will probe again later\n",
mac_cb->mac_id);
+ put_device(&pdev->dev);
return -EPROBE_DEFER;
}

rc = hns_mac_register_phydev(mii_bus, mac_cb, addr);
if (!rc)
dev_dbg(mac_cb->dev, "mac%d register phy addr:%d\n",
mac_cb->mac_id, addr);

return rc;
}

Looks like if put_device() is missing it will also be missing in case
hns_mac_register_phydev() returns an error.

2022-01-12 10:39:30

by Miaoqian Lin

Subject: [PATCH v2] net: hns: Fix missing put_device() call in hns_mac_register_phy

We need to drop the reference taken by hns_dsaf_find_platform_device
Missing put_device() may cause refcount leak.

Fixes: 804ffe5c6197 ("net: hns: support deferred probe when no mdio")
Signed-off-by: Miaoqian Lin <[email protected]>
---
Changes in v2:
- add put_device when hns_mac_register_phydev fails.
---
drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
index 7edf8569514c..cba9d92e057e 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c
@@ -764,13 +764,16 @@ static int hns_mac_register_phy(struct hns_mac_cb *mac_cb)
dev_err(mac_cb->dev,
"mac%d mdio is NULL, dsaf will probe again later\n",
mac_cb->mac_id);
+ put_device(&pdev->dev);
return -EPROBE_DEFER;
}

rc = hns_mac_register_phydev(mii_bus, mac_cb, addr);
- if (!rc)
+ if (!rc) {
dev_dbg(mac_cb->dev, "mac%d register phy addr:%d\n",
mac_cb->mac_id, addr);
+ put_device(&pdev->dev);
+ }

return rc;
}
--
2.17.1

2022-01-12 13:46:12

by Andrew Lunn

Subject: Re: [PATCH v2] net: hns: Fix missing put_device() call in hns_mac_register_phy

On Wed, Jan 12, 2022 at 10:39:19AM +0000, Miaoqian Lin wrote:
> We need to drop the reference taken by hns_dsaf_find_platform_device
> Missing put_device() may cause refcount leak.

Is the put also missing on driver unload?

As a fix for net, it might be better to rename
dsaf_find_platform_device() to dsaf_get_platform_device() and add a
dsaf_put_platform_device(). Add similar undo functions where ever
needed, and make sure they get called.

Andrew