Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753372AbbFXWAc (ORCPT ); Wed, 24 Jun 2015 18:00:32 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:57464 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753218AbbFXV7d (ORCPT ); Wed, 24 Jun 2015 17:59:33 -0400 Message-ID: <558B2842.2030007@codeaurora.org> Date: Wed, 24 Jun 2015 14:59:30 -0700 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, John Stultz , Steven Rostedt , "Paul E. McKenney" , Nicolas Pitre Subject: Re: [PATCH] ARM64: smp: Silence suspicious RCU usage with ipi tracepoints References: <1435176858-9568-1-git-send-email-sboyd@codeaurora.org> <20150624212930.GC12596@twins.programming.kicks-ass.net> In-Reply-To: <20150624212930.GC12596@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1118 Lines: 25 On 06/24/2015 02:29 PM, Peter Zijlstra 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'. Fair enough. I can resend or whoever applies this patch can s/Silence/Fix/ on the $subject. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- 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/