From: Daniel Borkmann <daniel@iogearbox.net>
To: Song Liu <liu.song.a23@gmail.com>,
Eugene Syromiatnikov <esyr@redhat.com>
Cc: netdev@vger.kernel.org, open list <linux-kernel@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>,
Alexei Starovoitov <ast@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jiri Olsa <jolsa@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Lawrence Brakmo <brakmo@fb.com>, Andrey Ignatov <rdna@fb.com>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
John Fastabend <john.fastabend@gmail.com>,
"Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH bpf 1/2] bpf: fix alignment of netns_dev/netns_ino fields in bpf_{map,prog}_info
Date: Sat, 2 Jun 2018 05:28:46 +0200 [thread overview]
Message-ID: <e0bc258a-19c1-50bd-4cc6-a7d50be88169@iogearbox.net> (raw)
In-Reply-To: <CAPhsuW4v=V0mbz07xe_shd68WP3BoV8iofxyVGApi+sL9kgzWQ@mail.gmail.com>
On 05/29/2018 07:17 PM, Song Liu wrote:
> On Sun, May 27, 2018 at 4:28 AM, Eugene Syromiatnikov <esyr@redhat.com> wrote:
>> Recent introduction of netns_dev/netns_ino to bpf_map_info/bpf_prog info
>> has broken compat, as offsets of these fields are different in 32-bit
>> and 64-bit ABIs. One fix (other than implementing compat support in
>> syscall in order to handle this discrepancy) is to use __aligned_u64
>> instead of __u64 for these fields.
>>
>> Reported-by: Dmitry V. Levin <ldv@altlinux.org>
>> Fixes: 52775b33bb507 ("bpf: offload: report device information about
>> offloaded maps")
>> Fixes: 675fc275a3a2d ("bpf: offload: report device information for
>> offloaded programs")
>>
>> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
>> ---
>> include/uapi/linux/bpf.h | 8 ++++----
>> tools/include/uapi/linux/bpf.h | 8 ++++----
>> 2 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>> index c5ec897..903010a 100644
>> --- a/include/uapi/linux/bpf.h
>> +++ b/include/uapi/linux/bpf.h
>> @@ -1017,8 +1017,8 @@ struct bpf_prog_info {
>> __aligned_u64 map_ids;
>> char name[BPF_OBJ_NAME_LEN];
>> __u32 ifindex;
>> - __u64 netns_dev;
>> - __u64 netns_ino;
>> + __aligned_u64 netns_dev;
>> + __aligned_u64 netns_ino;
>> } __attribute__((aligned(8)));
>
> Shall we add a __u32 padding variable before netns_dev? We can use it
> for in the future.
Agree with Song, and definitely prefer that approach since we already use the hole
as a bitfield in net-next; like this https://patchwork.ozlabs.org/patch/924415/.
next prev parent reply other threads:[~2018-06-02 3:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-27 11:28 [PATCH bpf 1/2] bpf: fix alignment of netns_dev/netns_ino fields in bpf_{map,prog}_info Eugene Syromiatnikov
2018-05-29 17:17 ` Song Liu
2018-06-02 3:28 ` Daniel Borkmann [this message]
2018-05-30 18:18 ` Dmitry V. Levin
2018-06-01 3:12 ` Dmitry V. Levin
2018-06-01 8:41 ` Alexei Starovoitov
2018-06-01 11:12 ` Dmitry V. Levin
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