Messages in this thread Patch in this message | | | From | Pavel Skripkin <> | Subject | [PATCH] phy: mdio: fix memory leak | Date | Mon, 27 Sep 2021 14:20:17 +0300 |
| |
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() was just calling kfree(dev) in case of MDIOBUS_ALLOCATED state
To avoid this behaviour we can add new intermediate state, which means, that we have called device_regiter(), but failed on any of the next steps. Clean up process for this state is the same as for MDIOBUS_UNREGISTERED, but MDIOBUS_UNREGISTERED name does not fit to the logic described above.
Fixes: 46abc02175b3 ("phylib: give mdio buses a device tree presence") Reported-and-tested-by: syzbot+398e7dc692ddbbb4cfec@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- drivers/net/phy/mdio_bus.c | 4 +++- include/linux/phy.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 53f034fc2ef7..ed764638b449 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -540,6 +540,8 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) return -EINVAL; } + bus->state = MDIOBUS_DEV_REGISTERED; + mutex_init(&bus->mdio_lock); mutex_init(&bus->shared_lock); @@ -647,7 +649,7 @@ void mdiobus_free(struct mii_bus *bus) return; } - BUG_ON(bus->state != MDIOBUS_UNREGISTERED); + BUG_ON(bus->state != MDIOBUS_UNREGISTERED && bus->state != MDIOBUS_DEV_REGISTERED); bus->state = MDIOBUS_RELEASED; put_device(&bus->dev); diff --git a/include/linux/phy.h b/include/linux/phy.h index 736e1d1a47c4..41d2ccdacd5e 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -343,6 +343,7 @@ struct mii_bus { MDIOBUS_REGISTERED, MDIOBUS_UNREGISTERED, MDIOBUS_RELEASED, + MDIOBUS_DEV_REGISTERED, } state; /** @dev: Kernel device representation */ -- 2.33.0
| |