Messages in this thread | | | Date | Tue, 28 Sep 2021 15:23:48 +0300 | From | Dan Carpenter <> | Subject | Re: [PATCH] net: mdiobus: Fix memory leak in __mdiobus_register |
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On Tue, Sep 28, 2021 at 02:45:39PM +0300, Pavel Skripkin wrote: > On 9/28/21 14:30, Dan Carpenter wrote: > > On Tue, Sep 28, 2021 at 02:09:06PM +0300, Pavel Skripkin wrote: > > > > Huh... You're right that the log should say "failed to register". But > > I don't think that's the correct syzbot link for your patch either > > because I don't think anyone calls mdiobus_free() if > > __devm_mdiobus_register() fails. I have looked at these callers. It > > would be a bug as well. > > > > mdiobus_free() is called in case of ->probe() failure, because devres clean > up function for bus is devm_mdiobus_free(). It simply calls mdiobus_free(). > > > So, i imagine following calltrace: > > ax88772_bind > ax88772_init_mdio > devm_mdiobus_alloc() <- bus registered as devres > devm_mdiobus_register() <- fail (->probe failure) > > ... > > devres_release_all > mdiobus_free()
Argh... Crap. You're right. There is just one bug. No need to change __devm_mdiobus_register() and trying to do that would lead to a UAF.
Your patch is the correct fix but with the modifications we discussed.
regards, dan carpenter
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