Date: Wed, 24 Jun 2015 21:01:31 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        John Stultz <john.stultz@linaro.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Nicolas Pitre <nicolas.pitre@linaro.org>
Subject: Re: [PATCH] ARM64: smp: Silence suspicious RCU usage with ipi
 tracepoints
Message-ID: <20150624210131.384d5505@gandalf.local.home>
In-Reply-To: <20150624212930.GC12596@twins.programming.kicks-ass.net>
References: <1435176858-9568-1-git-send-email-sboyd@codeaurora.org>
	<20150624212930.GC12596@twins.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1034
Lines: 24

On Wed, 24 Jun 2015 23:29:30 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Jun 24, 2015 at 01:14:18PM -0700, Stephen Boyd wrote:
> > John Stultz reported an RCU splat on ARM with ipi trace events
> > enabled. It looks like the same problem exists on ARM64.
> > 
> > At this point in the IPI handling path we haven't called
> > irq_enter() yet, so RCU doesn't know that we're about to exit
> > idle and properly warns that we're using RCU from an idle CPU.
> > Use trace_ipi_entry_rcuidle() instead of trace_ipi_entry() so
> > that RCU is informed about our exit from idle.
> 
> I have a problem with $subject. It says 'silence', whereas afaict this
> fixes an actual bug, so it should be 'fixes'.

Agreed, otherwise Acked-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/