Messages in this thread | | | Date | Thu, 11 Nov 2021 22:08:24 +0800 (GMT+08:00) | From | "Lin Ma" <> | Subject | Re: Re: [PATCH v0] hamradio: delete unnecessary free_netdev() |
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Hi Jakub
> On Thu, 11 Nov 2021 22:00:07 +0800 Lin Ma wrote: > > The former patch "defer 6pack kfree after unregister_netdev" adds > > free_netdev() function in sixpack_close(), which is a bad copy from the > > similar code in mkiss_close(). However, this free is unnecessary as the > > flag needs_free_netdev is set to true in sp_setup(), hence the > > unregister_netdev() will free the netdev automatically. > > > > Signed-off-by: Lin Ma <linma@zju.edu.cn> > > --- > > drivers/net/hamradio/6pack.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c > > index bfdf89e54752..180c8f08169b 100644 > > --- a/drivers/net/hamradio/6pack.c > > +++ b/drivers/net/hamradio/6pack.c > > @@ -677,8 +677,6 @@ static void sixpack_close(struct tty_struct *tty) > > /* Free all 6pack frame buffers after unreg. */ > > kfree(sp->rbuff); > > kfree(sp->xbuff); > > - > > - free_netdev(sp->dev); > > sp is netdev_priv() tho, so this is now a UAF. I'd go for removing the > needs_free_netdev = true instead. > > > } > > > > /* Perform I/O control on an active 6pack channel. */
Okay, that make senses, wait a minute.
Thanks Lin | |