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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 E60D9C43215 for ; Tue, 19 Nov 2019 12:14:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BED16222ED for ; Tue, 19 Nov 2019 12:14:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727952AbfKSMOe (ORCPT ); Tue, 19 Nov 2019 07:14:34 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:52124 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727432AbfKSMOe (ORCPT ); Tue, 19 Nov 2019 07:14:34 -0500 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1iX2Or-0003To-3p; Tue, 19 Nov 2019 13:14:29 +0100 Date: Tue, 19 Nov 2019 13:14:29 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org, Joel Fernandes , "Paul E. McKenney" Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Thomas Gleixner Subject: [PATCH] perf/core: Add SRCU annotation for pmus list walk Message-ID: <20191119121429.zhcubzdhm672zasg@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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