| Message ID | 5745dea4e12268a3f6b0772317f1cf0f49dab958.1632982651.git.paskripkin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v3,1/2] Revert "net: mdiobus: Fix memory leak in __mdiobus_register" | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Guessing tree name failed - patch did not apply |
On Thu, Sep 30, 2021 at 09:19:54AM +0300, Pavel Skripkin wrote: > Syzbot reported memory leak in MDIO bus interface, the problem was in > wrong state logic. > > MDIOBUS_ALLOCATED indicates 2 states: > 1. Bus is only allocated > 2. Bus allocated and __mdiobus_register() fails, but > device_register() was called > > In case of device_register() has been called we should call put_device() > to correctly free the memory allocated for this device, but mdiobus_free() > calls just kfree(dev) in case of MDIOBUS_ALLOCATED state > > To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED > _before_ calling device_register(), because put_device() should be > called even in case of device_register() failure. > > Link: https://lore.kernel.org/netdev/YVMRWNDZDUOvQjHL@shell.armlinux.org.uk/ > Fixes: 46abc02175b3 ("phylib: give mdio buses a device tree presence") > Reported-and-tested-by: syzbot+398e7dc692ddbbb4cfec@syzkaller.appspotmail.com > Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> > --- > > Changes in v3: > s/==/=/ > Added Dan's Reviewed-by tag > > Changes in v2: > Removed new state, since MDIOBUS_UNREGISTERED can be used. Also, moved > bus->state initialization _before_ device_register() call, because > Yanfei's patch is reverted in [v2 1/2] > > --- > drivers/net/phy/mdio_bus.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c > index 53f034fc2ef7..a5f910d4a7be 100644 > --- a/drivers/net/phy/mdio_bus.c > +++ b/drivers/net/phy/mdio_bus.c > @@ -534,6 +534,13 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) > bus->dev.groups = NULL; > dev_set_name(&bus->dev, "%s", bus->id); > > + /* We need to set state to MDIOBUS_UNREGISTERED to correctly realese Typo here. s/realese/release/ > + * the device in mdiobus_free() > + * > + * State will be updated later in this function in case of success > + */ > + bus->state = MDIOBUS_UNREGISTERED; > + > err = device_register(&bus->dev); > if (err) { > pr_err("mii_bus %s failed to register\n", bus->id);
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 53f034fc2ef7..a5f910d4a7be 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -534,6 +534,13 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) bus->dev.groups = NULL; dev_set_name(&bus->dev, "%s", bus->id); + /* We need to set state to MDIOBUS_UNREGISTERED to correctly realese + * the device in mdiobus_free() + * + * State will be updated later in this function in case of success + */ + bus->state = MDIOBUS_UNREGISTERED; + err = device_register(&bus->dev); if (err) { pr_err("mii_bus %s failed to register\n", bus->id);
Syzbot reported memory leak in MDIO bus interface, the problem was in wrong state logic. MDIOBUS_ALLOCATED indicates 2 states: 1. Bus is only allocated 2. Bus allocated and __mdiobus_register() fails, but device_register() was called In case of device_register() has been called we should call put_device() to correctly free the memory allocated for this device, but mdiobus_free() calls just kfree(dev) in case of MDIOBUS_ALLOCATED state To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED _before_ calling device_register(), because put_device() should be called even in case of device_register() failure. Link: https://lore.kernel.org/netdev/YVMRWNDZDUOvQjHL@shell.armlinux.org.uk/ Fixes: 46abc02175b3 ("phylib: give mdio buses a device tree presence") Reported-and-tested-by: syzbot+398e7dc692ddbbb4cfec@syzkaller.appspotmail.com Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- Changes in v3: s/==/=/ Added Dan's Reviewed-by tag Changes in v2: Removed new state, since MDIOBUS_UNREGISTERED can be used. Also, moved bus->state initialization _before_ device_register() call, because Yanfei's patch is reverted in [v2 1/2] --- drivers/net/phy/mdio_bus.c | 7 +++++++ 1 file changed, 7 insertions(+)