On 2018年01月14日 01:31, Cong Wang wrote:
On Thu, Jan 11, 2018 at 2:16 AM, Jason Wang <jasow...@redhat.com> wrote:
It looks to me what is actual missed is the cleanups tun_detach_all(). For
me the only case that could leak is
open
attach
ip link del link dev tap0
close or another set_iff()
So in this case, clean during close is not sufficient since it could be
attached to another device.
In this case, close() still calls tun_detach() with clean=true, so
with my patch, the tx_array is still cleaned. What am I missing here?
Are you implying clean=true is not sufficient?
Consider the corner case:
1) open
2) tun_set_iff() (which calls tun_attach to initialize skb_array)
3) ip link del link dev tap0 (which calls tun_detach_all())
4) tun_set_iff() (current codes does not forbid this and it will
allocate skb array again)
Consider the skb array was only initialized when attach it to a real
device, we should do the cleanup when we detach it from a device which
happens on two places:
- actively: close to an tun fd (__tun_deatch())
- passively: tun device was destroyed (tun_detach_all())
Thanks
