Messages in this thread | | | Date | Wed, 8 Dec 2021 15:58:38 -0800 | From | Jakub Kicinski <> | Subject | Re: [PATCH] tun: avoid double free in tun_free_netdev |
| |
On Wed, 8 Dec 2021 11:44:02 -0500 George Kennedy wrote: > > It looks like a lot of the problem is duplicate unwind. > > Why does err_free_flow, err_free_stat etc unwinds need to exist if > > the free_netdev is going to do same thing. > > Maybe instead do not call security_tun_dev_free_security(tun->security) > in err_free_flow if it's going to be done anyway in tun_free_netdev().
That won't be good either. register_netdevice() has multiple failure modes, it may or may not call the destructor depending on where it fails. Either the stuff that destructor undoes needs to be moved to ndo_init (which is what destructor always pairs with), or you can check dev->reg_state. If dev->reg_state is NETREG_UNREGISTERING that means the destructor will be caller later.
The ndo_init way is preferable, just cut and past the appropriate lines preceding registration into a ndo_init callback.
| |