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Date: Tue, 22 May 2018 20:35:51 -0700
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Y Song <ys114321@gmail.com>
Cc: Alban Crequy <alban.crequy@gmail.com>, netdev <netdev@vger.kernel.org>,
        linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org,
        cgroups@vger.kernel.org, Alban Crequy <alban@kinvolk.io>,
        tj@kernel.org
Subject: Re: [PATCH] [RFC] bpf: tracing: new helper bpf_get_current_cgroup_ino
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References: <20180513173318.21680-1-alban@kinvolk.io>
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On Tue, May 22, 2018 at 08:33:24PM -0700, Y Song wrote:
> +       struct cgroup *cgrp = task_dfl_cgroup(current);
> +       if (!cgrp)
> +               return -EINVAL;

why this check is needed?