From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: Alexei Starovoitov <alexei.starovoitov@gmail•com>
Cc: David Ahern <dsahern@gmail•com>, David Ahern <dsahern@kernel•org>,
Network Development <netdev@vger•kernel.org>,
"David S. Miller" <davem@davemloft•net>,
Jakub Kicinski <kuba@kernel•org>,
Prashant Bhole <prashantbhole.linux@gmail•com>,
Jason Wang <jasowang@redhat•com>,
Jesper Dangaard Brouer <brouer@redhat•com>,
Toshiaki Makita <toshiaki.makita1@gmail•com>,
Daniel Borkmann <daniel@iogearbox•net>,
John Fastabend <john.fastabend@gmail•com>,
Alexei Starovoitov <ast@kernel•org>,
Martin KaFai Lau <kafai@fb•com>, Song Liu <songliubraving@fb•com>,
Yonghong Song <yhs@fb•com>, Andrii Nakryiko <andriin@fb•com>,
David Ahern <dahern@digitalocean•com>
Subject: Re: [PATCH bpf-next 04/16] net: Add BPF_XDP_EGRESS as a bpf_attach_type
Date: Thu, 23 Apr 2020 19:05:42 +0200 [thread overview]
Message-ID: <874kta6sk9.fsf@toke.dk> (raw)
In-Reply-To: <CAADnVQ+GDR15oArpEGFFOvZ35WthHyL+b97zQUxjXbz-ec5CGw@mail.gmail.com>
Alexei Starovoitov <alexei.starovoitov@gmail•com> writes:
> On Thu, Apr 23, 2020 at 9:40 AM Toke Høiland-Jørgensen <toke@redhat•com> wrote:
>>
>> Alexei Starovoitov <alexei.starovoitov@gmail•com> writes:
>>
>> > On Wed, Apr 22, 2020 at 05:51:36PM +0200, Toke Høiland-Jørgensen wrote:
>> >> David Ahern <dsahern@gmail•com> writes:
>> >>
>> >> > On 4/22/20 9:27 AM, Toke Høiland-Jørgensen wrote:
>> >> >> And as I said in the beginning, I'm perfectly happy to be told why I'm
>> >> >> wrong; but so far you have just been arguing that I'm out of scope ;)
>> >> >
>> >> > you are arguing about a suspected bug with existing code that is no way
>> >> > touched or modified by this patch set, so yes it is out of scope.
>> >>
>> >> Your patch is relying on the (potentially buggy) behaviour, so I don't
>> >> think it's out of scope to mention it in this context.
>> >
>> > Sorry for slow reply.
>> > I'm swamped with other things atm.
>> >
>> > Looks like there is indeed a bug in prog_type_ext handling code that
>> > is doing
>> > env->ops = bpf_verifier_ops[tgt_prog->type];
>> > I'm not sure whether the verifier can simply add:
>> > prog->expected_attach_type = tgt_prog->expected_attach_type;
>> > and be done with it.
>> > Likely yes, since expected_attach_type must be zero at that point
>> > that is enforced by bpf_prog_load_check_attach().
>> > So I suspect it's a single line fix.
>>
>> Not quite: the check in bpf_tracing_prog_attach() that enforces
>> prog->expected_attach_type==0 also needs to go. So 5 lines :)
>
> prog_ext's expected_attach_type needs to stay zero.
> It needs to be inherited from tgt prog. Hence one line:
> prog->expected_attach_type = tgt_prog->expected_attach_type;
Not sure I follow you here? I ended up with the patch below - without
the first hunk I can't attach freplace funcs to an xdp egress prog
(since the expected_attach_type will have been propagated from
verification time), and so that check will fail. Or am I missing
something?
-Toke
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d85f37239540..40c3103c7233 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2381,10 +2381,6 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog)
}
break;
case BPF_PROG_TYPE_EXT:
- if (prog->expected_attach_type != 0) {
- err = -EINVAL;
- goto out_put_prog;
- }
break;
case BPF_PROG_TYPE_LSM:
if (prog->expected_attach_type != BPF_LSM_MAC) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 513d9c545176..41c31773a3c4 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10485,6 +10485,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return -EINVAL;
}
env->ops = bpf_verifier_ops[tgt_prog->type];
+ prog->expected_attach_type = tgt_prog->expected_attach_type;
}
if (!tgt_prog->jited) {
verbose(env, "Can attach to only JITed progs\n");
next prev parent reply other threads:[~2020-04-23 17:05 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 20:00 [PATCH bpf-next 00/16] net: Add support for XDP in egress path David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 01/16] net: Refactor convert_to_xdp_frame David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 02/16] net: Move handling of IFLA_XDP attribute out of do_setlink David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 03/16] net: Add XDP setup and query commands for Tx programs David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 04/16] net: Add BPF_XDP_EGRESS as a bpf_attach_type David Ahern
2020-04-21 10:14 ` Toke Høiland-Jørgensen
2020-04-21 12:50 ` David Ahern
2020-04-21 13:25 ` Toke Høiland-Jørgensen
2020-04-21 13:49 ` David Ahern
2020-04-22 11:21 ` Toke Høiland-Jørgensen
2020-04-22 14:51 ` David Ahern
2020-04-22 15:27 ` Toke Høiland-Jørgensen
2020-04-22 15:33 ` David Ahern
2020-04-22 15:51 ` Toke Høiland-Jørgensen
2020-04-22 15:56 ` David Ahern
2020-04-23 15:23 ` Toke Høiland-Jørgensen
2020-04-23 0:39 ` Alexei Starovoitov
2020-04-23 16:40 ` Toke Høiland-Jørgensen
2020-04-23 16:52 ` Alexei Starovoitov
2020-04-23 17:05 ` Toke Høiland-Jørgensen [this message]
2020-04-23 22:44 ` Alexei Starovoitov
2020-04-23 23:49 ` Toke Høiland-Jørgensen
2020-04-24 0:53 ` Alexei Starovoitov
2020-04-24 0:58 ` David Ahern
2020-04-24 8:55 ` Toke Høiland-Jørgensen
2020-04-20 20:00 ` [PATCH bpf-next 05/16] xdp: Add xdp_txq_info to xdp_buff David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 06/16] net: Add IFLA_XDP_EGRESS for XDP programs in the egress path David Ahern
2020-04-21 10:17 ` Toke Høiland-Jørgensen
2020-04-21 12:59 ` David Ahern
2020-04-21 13:27 ` Toke Høiland-Jørgensen
2020-04-20 20:00 ` [PATCH bpf-next 07/16] net: Rename do_xdp_generic to do_xdp_generic_rx David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 08/16] net: rename netif_receive_generic_xdp to do_generic_xdp_core David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 09/16] net: set XDP egress program on netdevice David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 10/16] net: Support xdp in the Tx path for packets as an skb David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 11/16] net: Support xdp in the Tx path for xdp_frames David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 12/16] libbpf: Add egress XDP support David Ahern
2020-04-21 10:20 ` Toke Høiland-Jørgensen
2020-04-21 13:03 ` David Ahern
2020-04-21 13:28 ` Toke Høiland-Jørgensen
2020-04-23 1:19 ` Andrii Nakryiko
2020-04-23 1:33 ` David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 13/16] bpftool: Add support for XDP egress David Ahern
2020-04-23 10:43 ` Quentin Monnet
2020-04-23 18:50 ` David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 14/16] selftest: Add test for xdp_egress David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 15/16] selftest: Add xdp_egress attach tests David Ahern
2020-04-20 20:00 ` [PATCH bpf-next 16/16] samples/bpf: add XDP egress support to xdp1 David Ahern
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=874kta6sk9.fsf@toke.dk \
--to=toke@redhat$(echo .)com \
--cc=alexei.starovoitov@gmail$(echo .)com \
--cc=andriin@fb$(echo .)com \
--cc=ast@kernel$(echo .)org \
--cc=brouer@redhat$(echo .)com \
--cc=dahern@digitalocean$(echo .)com \
--cc=daniel@iogearbox$(echo .)net \
--cc=davem@davemloft$(echo .)net \
--cc=dsahern@gmail$(echo .)com \
--cc=dsahern@kernel$(echo .)org \
--cc=jasowang@redhat$(echo .)com \
--cc=john.fastabend@gmail$(echo .)com \
--cc=kafai@fb$(echo .)com \
--cc=kuba@kernel$(echo .)org \
--cc=netdev@vger$(echo .)kernel.org \
--cc=prashantbhole.linux@gmail$(echo .)com \
--cc=songliubraving@fb$(echo .)com \
--cc=toshiaki.makita1@gmail$(echo .)com \
--cc=yhs@fb$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox