On Tue, Jul 7, 2020 at 4:56 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > On 7/8/20 1:43 AM, Stanislav Fomichev wrote: > > On Tue, Jul 7, 2020 at 2:42 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > >> > >> On 7/7/20 1:42 AM, Andrii Nakryiko wrote: > >>> On Mon, Jul 6, 2020 at 4:02 PM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote: > >>>> > >>>> Implement BPF_CGROUP_INET_SOCK_RELEASE hook that triggers > >>>> on inet socket release. It triggers only for userspace > >>>> sockets, the same semantics as existing BPF_CGROUP_INET_SOCK_CREATE. > >>>> > >>>> The only questionable part here is the sock->sk check > >>>> in the inet_release. Looking at the places where we > >>>> do 'sock->sk = NULL', I don't understand how it can race > >>>> with inet_release and why the check is there (it's been > >>>> there since the initial git import). Otherwise, the > >>>> change itself is pretty simple, we add a BPF hook > >>>> to the inet_release and avoid calling it for kernel > >>>> sockets. > >>>> > >>>> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx> > >>>> --- > >>>> include/linux/bpf-cgroup.h | 4 ++++ > >>>> include/uapi/linux/bpf.h | 1 + > >>>> kernel/bpf/syscall.c | 3 +++ > >>>> net/core/filter.c | 1 + > >>>> net/ipv4/af_inet.c | 3 +++ > >>>> 5 files changed, 12 insertions(+) > >>>> > >>> > >>> Looks good overall, but I have no idea about sock->sk NULL case. > >> > >> +1, looks good & very useful hook. For the sock->sk NULL case here's a related > >> discussion on why it's needed [0]. > > Thanks for the pointer! I'll resend a v5 with s/sock/sock_create/ you > > mentioned and will clean up the commit description a bit. > > Already fixed up the selftest and a typo in the commit desc there & applied it. Oh, awesome, thanks!
