[PATCH 6.0 0851/1073] r6040: Fix kmemleak in probe and remove

Greg Kroah-Hartman
2022-12-28T16:33:30Z

From: Li Zetao <lizetao1@huawei.com>

[ Upstream commit 7e43039a49c2da45edc1d9d7c9ede4003ab45a5f ]

There is a memory leaks reported by kmemleak:

unreferenced object 0xffff888116111000 (size 2048):
comm "modprobe", pid 817, jiffies 4294759745 (age 76.502s)
hex dump (first 32 bytes):
00 c4 0a 04 81 88 ff ff 08 10 11 16 81 88 ff ff ................
08 10 11 16 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff815bcd82>] kmalloc_trace+0x22/0x60
[<ffffffff827e20ee>] phy_device_create+0x4e/0x90
[<ffffffff827e6072>] get_phy_device+0xd2/0x220
[<ffffffff827e7844>] mdiobus_scan+0xa4/0x2e0
[<ffffffff827e8be2>] __mdiobus_register+0x482/0x8b0
[<ffffffffa01f5d24>] r6040_init_one+0x714/0xd2c [r6040]
...

The problem occurs in probe process as follows:
r6040_init_one:
mdiobus_register
mdiobus_scan <- alloc and register phy_device,
the reference count of phy_device is 3
r6040_mii_probe
phy_connect <- connect to the first phy_device,
so the reference count of the first
phy_device is 4, others are 3
register_netdev <- fault inject succeeded, goto error handling path

// error handling path
err_out_mdio_unregister:
mdiobus_unregister(lp->mii_bus);
err_out_mdio:
mdiobus_free(lp->mii_bus); <- the reference count of the first
phy_device is 1, it is not released
and other phy_devices are released
// similarly, the remove process also has the same problem

The root cause is traced to the phy_device is not disconnected when
removes one r6040 device in r6040_remove_one() or on error handling path
after r6040_mii probed successfully. In r6040_mii_probe(), a net ethernet
device is connected to the first PHY device of mii_bus, in order to
notify the connected driver when the link status changes, which is the
default behavior of the PHY infrastructure to handle everything.
Therefore the phy_device should be disconnected when removes one r6040
device or on error handling path.

Fix it by adding phy_disconnect() when removes one r6040 device or on
error handling path after r6040_mii probed successfully.

Fixes: 3831861b4ad8 ("r6040: implement phylib")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20221213125614.927754-1-lizetao1@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/rdc/r6040.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/rdc/r6040.c b/drivers/net/ethernet/rdc/r6040.c
index a6bf7d505178..322d4d72d2e0 100644
--- a/drivers/net/ethernet/rdc/r6040.c
+++ b/drivers/net/ethernet/rdc/r6040.c
@@ -1159,10 +1159,12 @@ static int r6040_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
err = register_netdev(dev);
if (err) {
dev_err(&pdev->dev, "Failed to register net device\n");
- goto err_out_mdio_unregister;
+ goto err_out_phy_disconnect;
}
return 0;

+err_out_phy_disconnect:
+ phy_disconnect(dev->phydev);
err_out_mdio_unregister:
mdiobus_unregister(lp->mii_bus);
err_out_mdio:
@@ -1186,6 +1188,7 @@ static void r6040_remove_one(struct pci_dev *pdev)
struct r6040_private *lp = netdev_priv(dev);

unregister_netdev(dev);
+ phy_disconnect(dev->phydev);
mdiobus_unregister(lp->mii_bus);
mdiobus_free(lp->mii_bus);
netif_napi_del(&lp->napi);
--
2.35.1