Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20200128072740.21272-1-frextrite@gmail.com>
In-Reply-To: <20200128072740.21272-1-frextrite@gmail.com>
From:   Jann Horn <jannh@google.com>
Date:   Tue, 28 Jan 2020 10:30:19 +0100
Message-ID: <CAG48ez3ZcO+kVPJVG6XpCPyGUKF2o4UJ6AVdgZXGQ6XJJpcdmg@mail.gmail.com>
Subject: Re: [PATCH] cred: Use RCU primitives to access RCU pointers
To:     Amol Grover <frextrite@gmail.com>
Cc:     David Howells <dhowells@redhat.com>,
        Shakeel Butt <shakeelb@google.com>,
        James Morris <jamorris@linux.microsoft.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        kernel list <linux-kernel@vger.kernel.org>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Joel Fernandes <joel@joelfernandes.org>,
        Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
        "Paul E . McKenney" <paulmck@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Jan 28, 2020 at 8:28 AM Amol Grover <frextrite@gmail.com> wrote:
> task_struct.cred and task_struct.real_cred are annotated by __rcu,

task_struct.cred doesn't actually have RCU semantics though, see
commit d7852fbd0f0423937fa287a598bfde188bb68c22. For task_struct.cred,
it would probably be more correct to remove the __rcu annotation?

> hence use rcu_access_pointer to access them.