From: Lee Jones <lee@kernel.org>
To: linux-kernel@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
bpf@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH v3 1/1] bpf: Drop unprotected find_vpid() in favour of find_get_pid()
Date: Thu, 8 Sep 2022 08:37:37 +0100 [thread overview]
Message-ID: <YxmbwRkJB3yJ58TM@google.com> (raw)
In-Reply-To: <YxmbPqKZMEXHL6sI@google.com>
On Thu, 08 Sep 2022, Lee Jones wrote:
> On Tue, 09 Aug 2022, Lee Jones wrote:
>
> > The documentation for find_vpid() clearly states:
> >
> > "Must be called with the tasklist_lock or rcu_read_lock() held."
> >
> > Presently we do neither.
> >
> > Let's use find_get_pid() which searches for the vpid, then takes a
> > reference to it preventing early free, all within the safety of
> > rcu_read_lock(). Once we have our reference we can safely make use of
> > it up until the point it is put.
> >
> > Cc: Alexei Starovoitov <ast@kernel.org>
> > Cc: Daniel Borkmann <daniel@iogearbox.net>
> > Cc: John Fastabend <john.fastabend@gmail.com>
> > Cc: Andrii Nakryiko <andrii@kernel.org>
> > Cc: Martin KaFai Lau <martin.lau@linux.dev>
> > Cc: Song Liu <song@kernel.org>
> > Cc: Yonghong Song <yhs@fb.com>
> > Cc: KP Singh <kpsingh@kernel.org>
> > Cc: Stanislav Fomichev <sdf@google.com>
> > Cc: Hao Luo <haoluo@google.com>
> > Cc: bpf@vger.kernel.org
> > Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
> > Acked-by: Jiri Olsa <jolsa@kernel.org>
> > Signed-off-by: Lee Jones <lee@kernel.org>
> > ---
> >
> > v1 => v2:
> > * Commit log update - description - no code differences
> >
> > v2 => v3:
> > * Commit log update - spelling of find_vpid() - no code differences
>
> Did anyone get a chance to look at this please?
>
> Would you like a [RESEND]?
Scrap that. I've just seen the last replies to v2.
Leave it with me.
--
Lee Jones [李琼斯]
prev parent reply other threads:[~2022-09-08 7:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-09 13:47 [PATCH v3 1/1] bpf: Drop unprotected find_vpid() in favour of find_get_pid() Lee Jones
2022-09-08 7:35 ` Lee Jones
2022-09-08 7:37 ` Lee Jones [this message]
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