Re: [PATCH 3/3 RESEND] auditsc: Do not use RCU primitive to read from cred pointer

From: Paul Moore <paul@paul-moore.com>
To: Amol Grover <frextrite@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	James Morris <jamorris@linux.microsoft.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jann Horn <jannh@google.com>, David Howells <dhowells@redhat.com>,
	Shakeel Butt <shakeelb@google.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Eric Paris <eparis@redhat.com>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org, linux-audit@redhat.com,
	Joel Fernandes <joel@joelfernandes.org>,
	Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
	"Paul E . McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH 3/3 RESEND] auditsc: Do not use RCU primitive to read from cred pointer
Date: Fri, 3 Apr 2020 15:25:42 -0400	[thread overview]
Message-ID: <CAHC9VhRFFoRQfOa=UkO2fNP-KNANrrKPnr0j+gNr7gtJp94W4A@mail.gmail.com> (raw)
In-Reply-To: <20200403075613.GA2788@workstation-portable>

On Fri, Apr 3, 2020 at 3:56 AM Amol Grover <frextrite@gmail.com> wrote:
> On Thu, Apr 02, 2020 at 08:56:36AM -0400, Paul Moore wrote:
> > On Thu, Apr 2, 2020 at 1:57 AM Amol Grover <frextrite@gmail.com> wrote:
> > > task_struct::cred is only used task-synchronously and does
> > > not require any RCU locks, hence, rcu_dereference_check is
> > > not required to read from it.
> > >
> > > Suggested-by: Jann Horn <jannh@google.com>
> > > Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > > Signed-off-by: Amol Grover <frextrite@gmail.com>
> > > ---
> > >  kernel/auditsc.c | 15 +++++----------
> > >  1 file changed, 5 insertions(+), 10 deletions(-)
> >
> > This is the exact same patch I ACK'd back in February, yes?
> >
> > https://lore.kernel.org/linux-audit/CAHC9VhQCbg1V290bYEZM+izDPRpr=XYXakohnDaMphkBBFgUaA@mail.gmail.com
> >
>
> Hi Paul,
>
> That's correct. I've resend the series out of the fear that the first 2
> patches might've gotten lost as it's been almost a month since I last
> sent them. Could you please ack this again, and if you don't mind could
> you please go through the other 2 patches and ack them aswell?

If you hadn't changed the patch at all, and it doesn't look like you
did, you could have (and likely should have) just carried over my ACK.
Regardless, I'll re-ACK it now (below).  As far as the other two
patches are concerned, they look okay to me but I would defer my ACK
to maintainer of that code.

Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com