From: Javier Honduvilla Coto <javierhonduco@fb•com>
To: Martin Lau <kafai@fb•com>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Yonghong Song <yhs@fb•com>, Kernel Team <Kernel-team@fb•com>
Subject: Re: [PATCH bpf-next 1/3] bpf: add bpf_progenyof helper
Date: Fri, 1 Mar 2019 17:43:42 +0000 [thread overview]
Message-ID: <20190301174335.GB99700@fb.com> (raw)
In-Reply-To: <20190227062639.jpzwmm63iygad5f7@kafai-mbp.dhcp.thefacebook.com>
On Wed, Feb 27, 2019 at 06:26:41AM +0000, Martin Lau wrote:
Sorry, accidentally did not reply to all your comments:
> On Tue, Feb 26, 2019 at 02:36:49PM -0800, Javier Honduvilla Coto wrote:
> > This patch adds the bpf_progenyof helper which receives a PID and returns
> What is progenof?
progenyof is a helper we'd love to have in thr kernel as right now
checking if the current process pid is among the progeny of some
arbitrary pid has several disadvantages. There are more details in the
first commit message
>
> > 1 if the process currently being executed is in the process hierarchy
> > including itself or 0 if not.
> >
> > This is very useful in tracing programs when we want to filter by a
> > given PID and all the children it might spawn. The current workarounds
> > most people implement for this purpose have issues:
> >
> > - Attaching to process spawning syscalls and dynamically add those PIDs
> > to some bpf map that would be used to filter is cumbersome and
> > potentially racy.
> > - Unrolling some loop to perform what this helper is doing consumes lots
> > of instructions. That and the impossibility to jump backwards makes it
> > really hard to be correct in really large process chains.
> >
> > Signed-off-by: Javier Honduvilla Coto <javierhonduco@fb•com>
> > ---
> > include/linux/bpf.h | 1 +
> > include/uapi/linux/bpf.h | 3 ++-
> > kernel/bpf/core.c | 1 +
> > kernel/bpf/helpers.c | 29 +++++++++++++++++++++++++++++
> > kernel/trace/bpf_trace.c | 2 ++
> > 5 files changed, 35 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index de18227b3d95..447395ba202b 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -921,6 +921,7 @@ extern const struct bpf_func_proto bpf_sk_redirect_map_proto;
> > extern const struct bpf_func_proto bpf_spin_lock_proto;
> > extern const struct bpf_func_proto bpf_spin_unlock_proto;
> > extern const struct bpf_func_proto bpf_get_local_storage_proto;
> > +extern const struct bpf_func_proto bpf_progenyof_proto;
> It seems only used in bpf_trace.c. Does it have to be here?
Yes, we need it in bpf_trace.c where we are requiring it
next prev parent reply other threads:[~2019-03-01 17:43 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-26 22:36 [PATCH bpf-next 0/3] bpf: add progenyof helper Javier Honduvilla Coto
2019-02-26 22:36 ` [PATCH bpf-next 1/3] bpf: add bpf_progenyof helper Javier Honduvilla Coto
2019-02-27 6:26 ` Martin Lau
2019-03-01 17:28 ` Javier Honduvilla Coto
2019-03-02 0:01 ` Martin Lau
2019-03-02 1:08 ` Javier Honduvilla Coto
2019-03-01 17:43 ` Javier Honduvilla Coto [this message]
2019-03-01 18:06 ` [PATCH v2 bpf-next 0/3] " Javier Honduvilla Coto
2019-03-01 18:06 ` [PATCH v2 bpf-next 1/3] " Javier Honduvilla Coto
2019-03-02 0:12 ` Martin Lau
2019-03-02 1:10 ` Javier Honduvilla Coto
2019-03-05 22:47 ` [PATCH v3 bpf-next 0/3] " Javier Honduvilla Coto
2019-03-05 22:47 ` [PATCH v3 bpf-next 1/3] " Javier Honduvilla Coto
2019-03-05 22:47 ` [PATCH v3 bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-03-05 22:47 ` [PATCH v3 bpf-next 3/3] bpf: add tests for bpf_progenyof Javier Honduvilla Coto
2019-03-07 9:26 ` [PATCH v3 bpf-next 0/3] bpf: add bpf_progenyof helper Daniel Borkmann
2019-03-22 22:42 ` Javier Honduvilla Coto
2019-03-22 22:38 ` [PATCH v4 " Javier Honduvilla Coto
2019-03-22 22:38 ` [PATCH v4 bpf-next 1/3] " Javier Honduvilla Coto
2019-03-25 14:17 ` Daniel Borkmann
2019-03-27 15:57 ` Javier Honduvilla Coto
2019-03-27 20:44 ` Brendan Gregg
2019-03-27 16:02 ` Javier Honduvilla Coto
2019-03-22 22:38 ` [PATCH v4 bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-03-22 22:38 ` [PATCH v4 bpf-next 3/3] bpf: add tests for bpf_progenyof Javier Honduvilla Coto
2019-04-10 20:36 ` [PATCH v5 bpf-next 0/3] bpf: add bpf_descendant_of helper Javier Honduvilla Coto
2019-04-10 20:36 ` [PATCH v5 bpf-next 1/3] " Javier Honduvilla Coto
2019-04-11 21:55 ` Daniel Borkmann
2019-04-12 0:20 ` Javier Honduvilla Coto
2019-04-10 20:36 ` [PATCH v5 bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-04-10 20:36 ` [PATCH v5 bpf-next 3/3] bpf: add tests for bpf_descendant_of Javier Honduvilla Coto
2019-04-11 17:59 ` [PATCH v5 bpf-next 0/3] bpf: add bpf_descendant_of helper Song Liu
2019-07-10 18:00 ` [PATCH v6 " Javier Honduvilla Coto
2019-07-10 18:00 ` [PATCH v6 bpf-next 1/3] " Javier Honduvilla Coto
2019-07-10 18:00 ` [PATCH v6 bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-07-10 18:00 ` [PATCH v6 bpf-next 3/3] bpf: add tests for bpf_descendant_of Javier Honduvilla Coto
2019-07-10 19:25 ` Andrii Nakryiko
2019-07-12 12:41 ` [PATCH v6 bpf-next 0/3] bpf: add bpf_descendant_of helper Daniel Borkmann
2019-03-01 18:06 ` [PATCH v2 bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-03-01 18:06 ` [PATCH v2 bpf-next 3/3] bpf: add tests for bpf_progenyof Javier Honduvilla Coto
2019-02-26 22:36 ` [PATCH bpf-next 2/3] bpf: sync kernel uapi headers Javier Honduvilla Coto
2019-02-26 22:36 ` [PATCH bpf-next 3/3] bpf: add tests for bpf_progenyof Javier Honduvilla Coto
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