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Date:   Mon, 12 Sep 2022 15:55:04 +0100
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Subject: Re: [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable
 function find_vpid()
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To:     Lee Jones <lee@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@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>, KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, bpf@vger.kernel.org
References: <20220912133855.1218900-1-lee@kernel.org>
From:   Yonghong Song <yhs@fb.com>
In-Reply-To: <20220912133855.1218900-1-lee@kernel.org>
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On 9/12/22 2:38 PM, Lee Jones wrote:
> The documentation for find_vpid() clearly states:
>

No need for the above extra line.

>    "Must be called with the tasklist_lock or rcu_read_lock() held."
> 
> Presently we do neither.

Presently we do neither for find_vpid() instance in bpf_task_fd_query().
Add proper rcu_read_lock/unlock() to fix the issue.

> 
> Cc: Jiri Olsa <jolsa@kernel.org>
> 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")
> Signed-off-by: Lee Jones <lee@kernel.org>

Ack with above a few suggestions for the commit message.

Acked-by: Yonghong Song <yhs@fb.com>