From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: Jesper Dangaard Brouer <brouer@redhat•com>, sameehj@amazon•com
Cc: netdev@vger•kernel.org, bpf@vger•kernel.org, zorik@amazon•com,
akiyano@amazon•com, gtzalik@amazon•com,
Daniel Borkmann <borkmann@iogearbox•net>,
Alexei Starovoitov <alexei.starovoitov@gmail•com>,
John Fastabend <john.fastabend@gmail•com>,
Alexander Duyck <alexander.duyck@gmail•com>,
Jeff Kirsher <jeffrey.t.kirsher@intel•com>,
David Ahern <dsahern@gmail•com>,
Willem de Bruijn <willemdebruijn.kernel@gmail•com>,
Ilias Apalodimas <ilias.apalodimas@linaro•org>,
Lorenzo Bianconi <lorenzo@kernel•org>,
Saeed Mahameed <saeedm@mellanox•com>,
brouer@redhat•com
Subject: Re: [PATCH RFC v2 29/33] xdp: allow bpf_xdp_adjust_tail() to grow packet size
Date: Tue, 14 Apr 2020 12:11:33 +0200 [thread overview]
Message-ID: <87v9m2nzqi.fsf@toke.dk> (raw)
In-Reply-To: <20200414115656.2f0e6ac0@carbon>
Jesper Dangaard Brouer <brouer@redhat•com> writes:
> On Wed, 08 Apr 2020 13:53:01 +0200 Jesper Dangaard Brouer <brouer@redhat•com> wrote:
>
>> diff --git a/net/core/filter.c b/net/core/filter.c
>> index 7628b947dbc3..4d58a147eed0 100644
>> --- a/net/core/filter.c
>> +++ b/net/core/filter.c
>> @@ -3422,12 +3422,26 @@ static const struct bpf_func_proto bpf_xdp_adjust_head_proto = {
>>
>> BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset)
>> {
>> + void *data_hard_end = xdp_data_hard_end(xdp);
>> void *data_end = xdp->data_end + offset;
>>
> [...]
>> + /* DANGER: ALL drivers MUST be converted to init xdp->frame_sz
>> + * - Adding some chicken checks below
>> + * - Will (likely) not be for upstream
>> + */
>> + if (unlikely(xdp->frame_sz < (xdp->data_end - xdp->data_hard_start))) {
>> + WARN(1, "Too small xdp->frame_sz = %d\n", xdp->frame_sz);
>> + return -EINVAL;
>> + }
>> + if (unlikely(xdp->frame_sz > PAGE_SIZE)) {
>> + WARN(1, "Too BIG xdp->frame_sz = %d\n", xdp->frame_sz);
>> + return -EINVAL;
>> + }
>
> Any opinions on above checks?
> Should they be removed or kept?
>
> The idea is to catch drivers that forgot to update xdp_buff->frame_sz,
> by doing some sanity checks on this uninit value. If I correctly
> updated all XDP drivers in this patchset, then these checks should be
> unnecessary, but will this be valuable for driver developers converting
> new drivers to XDP to have these WARN checks?
Hmm, I wonder if there's a way we could have these kinds of checks
available, but disabled by default? A new macro (e.g.,
XDP_CHECK(condition)) that is only enabled when some debug option is
enabled in the kernel build, perhaps? Or just straight ifdef'ing them
out, but maybe a macro would be generally useful?
-Toke
next prev parent reply other threads:[~2020-04-14 10:11 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <158634658714.707275.7903484085370879864.stgit@firesoul>
2020-04-08 11:50 ` [PATCH RFC v2 01/33] xdp: add frame size to xdp_buff Jesper Dangaard Brouer
2020-04-08 17:53 ` Jakub Kicinski
2020-04-09 0:48 ` Saeed Mahameed
2020-04-09 1:13 ` Jakub Kicinski
2020-04-09 23:07 ` Saeed Mahameed
2020-04-09 23:27 ` Jakub Kicinski
2020-04-14 14:16 ` Jesper Dangaard Brouer
2020-04-09 0:50 ` Saeed Mahameed
2020-04-16 13:02 ` Jesper Dangaard Brouer
2020-04-17 23:09 ` Saeed Mahameed
2020-04-08 11:50 ` [PATCH RFC v2 02/33] bnxt: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-08 11:50 ` [PATCH RFC v2 03/33] sfc: add XDP frame size Jesper Dangaard Brouer
2020-04-08 11:50 ` [PATCH RFC v2 04/33] mvneta: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-08 11:50 ` [PATCH RFC v2 05/33] net: netsec: Add support for XDP frame size Jesper Dangaard Brouer
2020-04-08 13:09 ` Lorenzo Bianconi
2020-04-14 8:07 ` Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 06/33] net: XDP-generic determining " Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 07/33] xdp: xdp_frame add member frame_sz and handle in convert_to_xdp_frame Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 08/33] xdp: cpumap redirect use frame_sz and increase skb_tailroom Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 09/33] veth: adjust hard_start offset on redirect XDP frames Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 10/33] veth: xdp using frame_sz in veth driver Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 11/33] dpaa2-eth: add XDP frame size Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 12/33] hv_netvsc: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-08 14:56 ` Haiyang Zhang
2020-04-08 11:51 ` [PATCH RFC v2 13/33] qlogic/qede: " Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 14/33] net: ethernet: ti: add XDP frame size to driver cpsw Jesper Dangaard Brouer
2020-04-08 11:51 ` [PATCH RFC v2 15/33] ena: add XDP frame size to amazon NIC driver Jesper Dangaard Brouer
2020-04-22 8:39 ` Jubran, Samih
2020-04-08 11:51 ` [PATCH RFC v2 16/33] mlx4: add XDP frame size and adjust max XDP MTU Jesper Dangaard Brouer
2020-04-08 12:57 ` Tariq Toukan
2020-04-14 8:19 ` Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 17/33] mlx5: rx queue setup time determine frame_sz for XDP Jesper Dangaard Brouer
2020-04-08 12:52 ` Tariq Toukan
2020-04-16 12:04 ` Jesper Dangaard Brouer
2020-04-09 9:28 ` Maxim Mikityanskiy
2020-04-08 11:52 ` [PATCH RFC v2 18/33] net: thunderx: add XDP frame size Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 19/33] nfp: add XDP frame size to netronome driver Jesper Dangaard Brouer
2020-04-08 17:53 ` Jakub Kicinski
2020-04-14 14:02 ` Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 20/33] tun: add XDP frame size Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 21/33] vhost_net: also populate " Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 22/33] virtio_net: add XDP frame size in two code paths Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 23/33] ixgbe: fix XDP redirect on archs with PAGE_SIZE above 4K Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 24/33] ixgbe: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 25/33] ixgbevf: add XDP frame size to VF driver Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 26/33] i40e: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-08 21:48 ` David Miller
2020-04-14 10:16 ` Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 27/33] ice: " Jesper Dangaard Brouer
2020-04-08 11:52 ` [PATCH RFC v2 28/33] xdp: for Intel AF_XDP drivers add XDP frame_sz Jesper Dangaard Brouer
2020-04-08 17:31 ` Björn Töpel
2020-04-09 9:33 ` Maxim Mikityanskiy
2020-04-08 11:53 ` [PATCH RFC v2 29/33] xdp: allow bpf_xdp_adjust_tail() to grow packet size Jesper Dangaard Brouer
2020-04-09 3:31 ` Saeed Mahameed
2020-04-14 12:46 ` Jesper Dangaard Brouer
2020-04-18 3:33 ` Saeed Mahameed
2020-04-14 9:56 ` Jesper Dangaard Brouer
2020-04-14 10:11 ` Toke Høiland-Jørgensen [this message]
2020-04-08 11:53 ` [PATCH RFC v2 30/33] xdp: clear grow memory in bpf_xdp_adjust_tail() Jesper Dangaard Brouer
2020-04-08 21:49 ` David Miller
2020-04-14 9:43 ` Jesper Dangaard Brouer
2020-04-08 11:53 ` [PATCH RFC v2 31/33] bpf: add xdp.frame_sz in bpf_prog_test_run_xdp() Jesper Dangaard Brouer
2020-04-08 11:53 ` [PATCH RFC v2 32/33] selftests/bpf: adjust BPF selftest for xdp_adjust_tail Jesper Dangaard Brouer
2020-04-08 11:53 ` [PATCH RFC v2 33/33] selftests/bpf: xdp_adjust_tail add grow tail tests Jesper Dangaard Brouer
2020-04-08 16:55 ` [PATCH RFC v2 00/33] XDP extend with knowledge of frame size Alexei Starovoitov
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