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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 E634CC73C41 for ; Tue, 9 Jul 2019 13:48:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF0052173E for ; Tue, 9 Jul 2019 13:48:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562680112; bh=rQnB7ykCXfFzqRJ88jyj9sjrvLqMIKiZ1fC4xlwXPCU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mbjbZn1CZH9QB4aPUCwDYG2KC7qqB42QMdFsK1W8LADmr+qNVZVMHEhn6gmxGy/p+ p3BuoJJcGMYy/CNfXuvhauYbd1zb00WkUyFmrJnENkc3JoEqHQJSJcGVf1Se62U8Mp DzwOAOVkK9U8T56MR+c4/BqYOoOtU7wiUe+mxBf8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726961AbfGINsb (ORCPT ); Tue, 9 Jul 2019 09:48:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:40648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725947AbfGINsa (ORCPT ); Tue, 9 Jul 2019 09:48:30 -0400 Received: from lerouge.home (lfbn-ncy-1-174-150.w83-194.abo.wanadoo.fr [83.194.254.150]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7D9362171F; Tue, 9 Jul 2019 13:48:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562680109; bh=rQnB7ykCXfFzqRJ88jyj9sjrvLqMIKiZ1fC4xlwXPCU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YsYBq1fJNBKhqhCCFTzZmyhaLyf5WY3mKf53CUpCh2VP190YEeTaxGHeAGLqiM/ad bksqTUk628Ze+yiRcPcZfNKxF25NnlaXzxI0eD4dZAFLm8eIypTQC8MJDy0LkpH0ki FNmcBfuh+XXmC8RSrVQdPCnF6eSJzaEg3tkm+PX8= From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Namhyung Kim , Peter Zijlstra , Dmitry Vyukov , Borislav Petkov , syzbot+370a6b0f11867bf13515@syzkaller.appspotmail.com, Jiri Olsa , Ingo Molnar , Arnaldo Carvalho de Melo , Masami Hiramatsu Subject: [PATCH 1/2] perf: Allow a pmu to pin context Date: Tue, 9 Jul 2019 15:48:20 +0200 Message-Id: <20190709134821.8027-2-frederic@kernel.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190709134821.8027-1-frederic@kernel.org> References: <20190709134821.8027-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some PMUs rely on the fact that struct perf_event::hw::target always point to the actual event target during the whole event lifecycle, ie: from pmu::init() to event::destroy(). Now perf event ctx swapping on task sched switch breaks that guarantee. Solve that with providing a way for a PMU to pin the context of an event. Reported-by: syzbot+370a6b0f11867bf13515@syzkaller.appspotmail.com Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Dmitry Vyukov Cc: Namhyung Kim Cc: Jiri Olsa Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Signed-off-by: Frederic Weisbecker --- include/linux/perf_event.h | 2 ++ kernel/events/core.c | 6 ++++++ 2 files changed, 8 insertions(+) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 2ddae518dce6..ea700a193865 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -273,6 +273,8 @@ struct pmu { /* number of address filters this PMU can do */ unsigned int nr_addr_filters; + int pin_ctx; + /* * Fully disable/enable this PMU, can be used to protect from the PMI * as well as for lazy/batch writing of the MSRs. diff --git a/kernel/events/core.c b/kernel/events/core.c index 23efe6792abc..6b4bc6fc47aa 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1689,6 +1689,9 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) ctx->nr_stat++; ctx->generation++; + + if (event->pmu->pin_ctx) + ctx->pin_count++; } /* @@ -1885,6 +1888,9 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) perf_event_set_state(event, PERF_EVENT_STATE_OFF); ctx->generation++; + + if (event->pmu->pin_ctx) + ctx->pin_count--; } static void perf_group_detach(struct perf_event *event) -- 2.21.0