From patchwork Fri May 8 12:30:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 226071 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=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 2898FC47254 for ; Fri, 8 May 2020 13:23:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 06974208CA for ; Fri, 8 May 2020 13:23:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588944224; bh=V2OjuT9f/QpJ6BnqvZuXrCXGGWej49JIhebHk+sWrnc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JWB7Dt37JLSRrfExbNUyRcHuaHOitaCdh0dd417Wbtcd1dRomDT9kg9ljqQWwk9pE B1qtilucyhTPr8U1qv3zzR3vYzXbcpYh+yXoyxSS0IWIPs/aDZ17gHsqz3Y8KzY6No ro2W4NILVjehSI0h9cTNZ1WLMk57gEKc9kOfflYI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728275AbgEHMhz (ORCPT ); Fri, 8 May 2020 08:37:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:52494 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728264AbgEHMhx (ORCPT ); Fri, 8 May 2020 08:37:53 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AF937207DD; Fri, 8 May 2020 12:37:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588941472; bh=V2OjuT9f/QpJ6BnqvZuXrCXGGWej49JIhebHk+sWrnc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LshjoaUQDpkXUljuqs+BYAuwk95HF3h2C7zqujAcNc+W4ZCqUVvGjmyBaP1WXAjtm dgOZBbx82sGwK/KuFsLQuEgiCxCuPqaoe9dP5Gv3dAG5nfqnKEBEfVZkTDZwYLYnCB fGQQCYGS/4dE4fwYTf/6jDfk05pA2fOp4XngsMEs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stephane Eranian , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Thomas Gleixner , Vince Weaver , jolsa@kernel.org, kan.liang@intel.com, Ingo Molnar Subject: [PATCH 4.4 045/312] perf/x86: Fix filter_events() bug with event mappings Date: Fri, 8 May 2020 14:30:36 +0200 Message-Id: <20200508123127.726833611@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123124.574959822@linuxfoundation.org> References: <20200508123124.574959822@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Stephane Eranian commit 61b87cae6361ea6af161c1ffa549898892707b19 upstream. This patch fixes a bug in the filter_events() function. The patch fixes the bug whereby if some mappings did not exist, e.g., STALLED_CYCLES_FRONTEND, then any event after it in the attrs array would disappear from the published list of events in /sys/devices/cpu/events. This could be verified easily on any system post SNB (which do not publish STALLED_CYCLES_FRONTEND): $ ./perf stat -e cycles,ref-cycles true Performance counter stats for 'true': 1,217,348 cycles ref-cycles The problem is that in filter_events() there is an assumption that the argument (attrs) is organized in increasing continuous event indexes related to the event_map(). But if we remove the non-supported events by shifing the position in the array, then the lookup x86_pmu.event_map() needs to compensate for it, otherwise we are looking up the wrong index. This patch corrects this problem by compensating for the deleted events and with that ref-cycles reappears (here shown on Haswell): $ perf stat -e ref-cycles,cycles true Performance counter stats for 'true': 4,525,910 ref-cycles 1,064,920 cycles 0.002943888 seconds time elapsed Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Cc: jolsa@kernel.org Cc: kan.liang@intel.com Fixes: 8300daa26755 ("perf/x86: Filter out undefined events from sysfs events attribute") Link: http://lkml.kernel.org/r/1449516805-6637-1-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/perf_event.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1550,6 +1550,7 @@ static void __init filter_events(struct { struct device_attribute *d; struct perf_pmu_events_attr *pmu_attr; + int offset = 0; int i, j; for (i = 0; attrs[i]; i++) { @@ -1558,7 +1559,7 @@ static void __init filter_events(struct /* str trumps id */ if (pmu_attr->event_str) continue; - if (x86_pmu.event_map(i)) + if (x86_pmu.event_map(i + offset)) continue; for (j = i; attrs[j]; j++) @@ -1566,6 +1567,14 @@ static void __init filter_events(struct /* Check the shifted attr. */ i--; + + /* + * event_map() is index based, the attrs array is organized + * by increasing event index. If we shift the events, then + * we need to compensate for the event_map(), otherwise + * we are looking up the wrong event in the map + */ + offset++; } }