From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F45BC432C0 for ; Fri, 29 Nov 2019 20:05:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D7BF21721 for ; Fri, 29 Nov 2019 20:05:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="IU0LNMh0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727113AbfK2UFZ (ORCPT ); Fri, 29 Nov 2019 15:05:25 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:38923 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727043AbfK2UFZ (ORCPT ); Fri, 29 Nov 2019 15:05:25 -0500 Received: by mail-pj1-f66.google.com with SMTP id v93so10470144pjb.6 for ; Fri, 29 Nov 2019 12:05:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=5ipR+DrBtOJQIudnRaII7nJ3+mq7nKbRqBwicLRMc3w=; b=IU0LNMh0TWniaggb1y5v7B/hYj06AGeQ6rFf4JXFP3ecy8Snmq/f80SwI5lmzFWIrJ tWeJyOxzIUhXa6LVLo+l/RdrzAEalAseSjkKIbR+FPLLc9VzYIasV3qKMRq0GnJU0azI ZcBiRNEHd7jjx1UEILokbjyRcOPFK6vVOXhrA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=5ipR+DrBtOJQIudnRaII7nJ3+mq7nKbRqBwicLRMc3w=; b=R6Xv595X33LBmjnyO+3j8M7dT0QuWpRQsZIwhZbgwqeh2+kxlQgTz0Mo4QHduRcASL oZJe3FfLtmb3vUsue0kMPwzy3ajeHIxivcyQjSsuJJ0tw/U4Wx9h1/MBo+5Pd999JfUo X6KZ85v1xV/Hzz4whtaamKKiOfPbRlNiFLsKmI8pSK6PV01KuEXQfVHzRHI9Nl6YwXQy SrZGNX03XgBl/rI5P3gyHvRJ9BijjMz1X1AzhcgLBOXuBHIJz6Lgn5S6EXFdgfR+hVCb YsHBKJeCf7ztsvn21a2J/GMYyK8Tx0A29dyWE4Tcm//pshx665aV56c5R5SC60AQsrL8 Egcg== X-Gm-Message-State: APjAAAWQFGvE/IJHybviU2HeRFyrt+rNKLqGYF1EqaFUHOmn9eoB9Te5 fjA2pBJWjJQGpLCWv0qeYxpbk4A76ac= X-Google-Smtp-Source: APXvYqzv+PIer9ks5zR5Vza4ROybRs9nR2wonFy59tez+ucGy/ExMOXQl27Izq38p0bVRbv+ekYwvw== X-Received: by 2002:a17:90a:aa96:: with SMTP id l22mr19758027pjq.112.1575057924147; Fri, 29 Nov 2019 12:05:24 -0800 (PST) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id 83sm25542605pgh.12.2019.11.29.12.05.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Nov 2019 12:05:23 -0800 (PST) Date: Fri, 29 Nov 2019 15:05:22 -0500 From: Joel Fernandes To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, "Paul E. McKenney" , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Thomas Gleixner Subject: Re: [PATCH] perf/core: Add SRCU annotation for pmus list walk Message-ID: <20191129200522.GA239292@google.com> References: <20191119121429.zhcubzdhm672zasg@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191119121429.zhcubzdhm672zasg@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 19, 2019 at 01:14:29PM +0100, Sebastian Andrzej Siewior wrote: > Since commit > 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking") > > there is an additional check to ensure that a RCU related lock is held > while the RCU list is iterated. > This section holds the SRCU reader lock instead. > > Add annotation to list_for_each_entry_rcu() that pmus_srcu must be > acquired during the list traversal. > Reviewed-by: Joel Fernandes (Google) thanks, - Joel > Signed-off-by: Sebastian Andrzej Siewior > --- > > I see the warning in in v5.4-rc during boot. For some reason I don't see > it in tip/master during boot but "perf stat w" triggers it again (among > other things). > > kernel/events/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 5224388872069..dbb3b26a55612 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -10497,7 +10497,7 @@ static struct pmu *perf_init_event(struct perf_event *event) > goto unlock; > } > > - list_for_each_entry_rcu(pmu, &pmus, entry) { > + list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { > ret = perf_try_init_event(pmu, event); > if (!ret) > goto unlock; > -- > 2.24.0 >