From: Pedro Tammela <pctammela@gmail.com>
To: Song Liu <songliubraving@fb.com>
Cc: Pedro Tammela <pctammela@mojatatu.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
Joe Stringer <joe@cilium.io>,
Quentin Monnet <quentin@isovalent.com>,
Yang Li <yang.lee@linux.alibaba.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH bpf-next] bpf: check flags in 'bpf_ringbuf_discard()' and 'bpf_ringbuf_submit()'
Date: Tue, 30 Mar 2021 11:22:37 -0300 [thread overview]
Message-ID: <CAKY_9u0J8gurpOhR9YZceH3N2jJFm=v5VLw3atjo==gTp_-RQg@mail.gmail.com> (raw)
In-Reply-To: <A175BAAD-39B2-4ECE-9BA0-D070E84484FF@fb.com>
Em seg., 29 de mar. de 2021 às 13:10, Song Liu <songliubraving@fb.com> escreveu:
>
>
>
> > On Mar 28, 2021, at 9:10 AM, Pedro Tammela <pctammela@gmail.com> wrote:
> >
> > The current code only checks flags in 'bpf_ringbuf_output()'.
> >
> > Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
> > ---
> > include/uapi/linux/bpf.h | 8 ++++----
> > kernel/bpf/ringbuf.c | 13 +++++++++++--
> > tools/include/uapi/linux/bpf.h | 8 ++++----
> > 3 files changed, 19 insertions(+), 10 deletions(-)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 100cb2e4c104..232b5e5dd045 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -4073,7 +4073,7 @@ union bpf_attr {
> > * Valid pointer with *size* bytes of memory available; NULL,
> > * otherwise.
> > *
> > - * void bpf_ringbuf_submit(void *data, u64 flags)
> > + * int bpf_ringbuf_submit(void *data, u64 flags)
>
> This should be "long" instead of "int".
>
> > * Description
> > * Submit reserved ring buffer sample, pointed to by *data*.
> > * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
> > @@ -4083,9 +4083,9 @@ union bpf_attr {
> > * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
> > * of new data availability is sent unconditionally.
> > * Return
> > - * Nothing. Always succeeds.
> > + * 0 on success, or a negative error in case of failure.
> > *
> > - * void bpf_ringbuf_discard(void *data, u64 flags)
> > + * int bpf_ringbuf_discard(void *data, u64 flags)
>
> Ditto. And same for tools/include/uapi/linux/bpf.h
>
> > * Description
> > * Discard reserved ring buffer sample, pointed to by *data*.
> > * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
> > @@ -4095,7 +4095,7 @@ union bpf_attr {
> > * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
> > * of new data availability is sent unconditionally.
> > * Return
> > - * Nothing. Always succeeds.
> > + * 0 on success, or a negative error in case of failure.
> > *
> > * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
> > * Description
> > diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
> > index f25b719ac786..f76dafe2427e 100644
> > --- a/kernel/bpf/ringbuf.c
> > +++ b/kernel/bpf/ringbuf.c
> > @@ -397,26 +397,35 @@ static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard)
> >
> > BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags)
> > {
> > + if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP)))
> > + return -EINVAL;
>
> We can move this check to bpf_ringbuf_commit().
I don't believe we can because in 'bpf_ringbuf_output()' the flag
checking in 'bpf_ringbuf_commit()' is already
too late.
>
> Thanks,
> Song
>
> [...]
Pedro
next prev parent reply other threads:[~2021-03-30 14:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-28 16:10 [PATCH bpf-next] bpf: add 'BPF_RB_MAY_WAKEUP' flag Pedro Tammela
2021-03-28 16:10 ` [PATCH bpf-next] bpf: check flags in 'bpf_ringbuf_discard()' and 'bpf_ringbuf_submit()' Pedro Tammela
2021-03-29 16:10 ` Song Liu
2021-03-30 14:22 ` Pedro Tammela [this message]
2021-03-30 18:12 ` Song Liu
2021-03-31 6:58 ` Andrii Nakryiko
2021-03-28 16:10 ` [PATCH bpf-next] libbpf: Add '_wait()' and '_nowait()' macros for 'bpf_ring_buffer__poll()' Pedro Tammela
2021-03-29 16:28 ` Song Liu
2021-03-31 18:59 ` Andrii Nakryiko
2021-03-29 16:05 ` [PATCH bpf-next] bpf: add 'BPF_RB_MAY_WAKEUP' flag Song Liu
2021-03-31 6:53 ` Andrii Nakryiko
2021-04-03 13:34 ` Pedro Tammela
2021-04-03 15:51 ` Andrii Nakryiko
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