4.9-stable review patch. If anyone has any objections, please let me know.
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From: Jon Mason jon.mason@broadcom.com
[ Upstream commit b60161668199ac62011c024adc9e66713b9554e7 ]
There is a potential unnecessary refcount decrement on error path of put_device(&pb->mii_bus->dev), as it is possible to avoid the of_mdio_find_bus() call if mux_bus is specified by the calling function.
The same put_device() is not called in the error path if the devm_kzalloc of pb fails. This caused the variable used in the put_device() to be changed, as the pb pointer was obviously not set up.
There is an unnecessary of_node_get() on child_bus_node if the of_mdiobus_register() is successful, as the for_each_available_child_of_node() automatically increments this. Thus the refcount on this node will always be +1 more than it should be.
There is no of_node_put() on child_bus_node if the of_mdiobus_register() call fails.
Finally, it is lacking devm_kfree() of pb in the error path. While this might not be technically necessary, it was present in other parts of the function. So, I am adding it where necessary to make it uniform.
Signed-off-by: Jon Mason jon.mason@broadcom.com Fixes: f20e6657a875 ("mdio: mux: Enhanced MDIO mux framework for integrated multiplexers") Fixes: 0ca2997d1452 ("netdev/of/phy: Add MDIO bus multiplexer support.") Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/phy/mdio-mux.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/drivers/net/phy/mdio-mux.c +++ b/drivers/net/phy/mdio-mux.c @@ -122,10 +122,9 @@ int mdio_mux_init(struct device *dev, pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); if (pb == NULL) { ret_val = -ENOMEM; - goto err_parent_bus; + goto err_pb_kz; }
- pb->switch_data = data; pb->switch_fn = switch_fn; pb->current_child = -1; @@ -154,6 +153,7 @@ int mdio_mux_init(struct device *dev, cb->mii_bus = mdiobus_alloc(); if (!cb->mii_bus) { ret_val = -ENOMEM; + devm_kfree(dev, cb); of_node_put(child_bus_node); break; } @@ -169,8 +169,8 @@ int mdio_mux_init(struct device *dev, if (r) { mdiobus_free(cb->mii_bus); devm_kfree(dev, cb); + of_node_put(child_bus_node); } else { - of_node_get(child_bus_node); cb->next = pb->children; pb->children = cb; } @@ -181,9 +181,11 @@ int mdio_mux_init(struct device *dev, return 0; }
+ devm_kfree(dev, pb); +err_pb_kz: /* balance the reference of_mdio_find_bus() took */ - put_device(&pb->mii_bus->dev); - + if (!mux_bus) + put_device(&parent_bus->dev); err_parent_bus: of_node_put(parent_bus_node); return ret_val;