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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 C8791C43387 for ; Fri, 11 Jan 2019 21:52:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B9F52183F for ; Fri, 11 Jan 2019 21:52:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=maine.edu header.i=@maine.edu header.b="bIJ+SWjA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726224AbfAKVw0 (ORCPT ); Fri, 11 Jan 2019 16:52:26 -0500 Received: from mail-qt1-f194.google.com ([209.85.160.194]:35031 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbfAKVw0 (ORCPT ); Fri, 11 Jan 2019 16:52:26 -0500 Received: by mail-qt1-f194.google.com with SMTP id v11so20526953qtc.2 for ; Fri, 11 Jan 2019 13:52:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=maine.edu; s=google; h=from:date:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=Rznx8m7oF3vk7OvtYn7TIPy51bBYUCQncQQQG14BSTc=; b=bIJ+SWjADDx+zmkSDmbB+mdj7BMAUd+EwHS8D2WLJU5Gikuze5O8djfkayy4uRPsr4 EMwr4WLjpuQC3Yguw5a74sCZ2D9pqaNJ5GM5Mnc90J9VrD2uSNmzLCwG1L0Tnw+YPeS4 LeXLLOwbCY/aUE03q4QQIb664QfQxC+fCpy48= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=Rznx8m7oF3vk7OvtYn7TIPy51bBYUCQncQQQG14BSTc=; b=qGFOGbHc43I3coH2B1Y+8i4WMVgjvoEgA+5NL0ryrPTG2HX6PWl2n8mGE0Hx7/kVst ST/V4tdVsje9vAOFQbacgPO8FIKdnwchKehWrM4wxMM5nzJ8nAOJVYH2BdgIoZZQ0bVO 8uh3pXeQIMHplz13miya8g0VVSCcA8kzYEg837oJz2yWcezE11YMEinKY03G585RfLLS e6DRcQhuUJwLWvj74EcrikEBu6lANolS/h8t+paMXgBVDWTmHRo4HWGsokmuNmhHq2bs kl5fNQ9VRwwd8zjhIqllOab2/bisZZNdJyBYaMK6WzgD/87m9A7VEr7vo3XaI03lbrJ1 Zohw== X-Gm-Message-State: AJcUukeIjilI2etOA63cetopUROn4VJ/F1C0eBYqwwfw5kYjIm/FOM9Q EDg83qISJ893TeZFx0cCh6jkVw== X-Google-Smtp-Source: ALg8bN7fmwtR9OElthFN+Ufvpq5laXZGEELE7MMzgx1zJKecNp8Zru3tELzyFuRE8JXZJCstrZmrIA== X-Received: by 2002:a0c:f8cb:: with SMTP id h11mr15835493qvo.134.1547243544107; Fri, 11 Jan 2019 13:52:24 -0800 (PST) Received: from macbook-air (weaver.eece.maine.edu. [130.111.218.23]) by smtp.gmail.com with ESMTPSA id m81sm24161384qkl.92.2019.01.11.13.52.22 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 11 Jan 2019 13:52:23 -0800 (PST) From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 11 Jan 2019 16:52:22 -0500 (EST) X-X-Sender: vince@macbook-air To: Peter Zijlstra cc: linux-kernel@vger.kernel.org, Ingo Molnar , Arnaldo Carvalho de Melo Subject: Re: perf: rdpmc bug when viewing all procs on remote cpu In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Jan 2019, Vince Weaver wrote: > On Thu, 10 Jan 2019, Vince Weaver wrote: > > > On Thu, 10 Jan 2019, Vince Weaver wrote: > > > > > However if you create an all-process attached to CPU event: > > > perf_event_open(attr, -1, X, -1, 0); > > > the mmap event index is set as if this were a valid event and so the rdpmc > > > succeeds even though it shouldn't (we're trying to read an event value > > > on a remote cpu with a local rdpmc). so on further looking at the code, it doesn't appear that rdpmc events are explicitly marked as unavailable in the attach-cpu or attach-pid case, it's just by luck the check for PERF_EVENT_STATE_ACTIVE catches most of the cases? should an explicit check be added to zero out userpg->index in cases where the event being measured is running on a different core? Vince