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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 18C0EC43603 for ; Tue, 17 Dec 2019 12:40:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EBA1724679 for ; Tue, 17 Dec 2019 12:40:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728352AbfLQMkd (ORCPT ); Tue, 17 Dec 2019 07:40:33 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:55286 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728269AbfLQMkE (ORCPT ); Tue, 17 Dec 2019 07:40:04 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1ihC8l-0001o4-Cg; Tue, 17 Dec 2019 13:39:51 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id BC1451C2A3D; Tue, 17 Dec 2019 13:39:50 +0100 (CET) Date: Tue, 17 Dec 2019 12:39:50 -0000 From: "tip-bot2 for Alexander Shishkin" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/urgent] perf/x86/intel/bts: Fix the use of page_private() Cc: Alexander Shishkin , "Peter Zijlstra (Intel)" , Jiri Olsa , Vince Weaver , Ingo Molnar , Arnaldo Carvalho de Melo , x86 , LKML In-Reply-To: <20191205142853.28894-2-alexander.shishkin@linux.intel.com> References: <20191205142853.28894-2-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Message-ID: <157658639063.30329.9964492624988033137.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the perf/urgent branch of tip: Commit-ID: ff61541cc6c1962957758ba433c574b76f588d23 Gitweb: https://git.kernel.org/tip/ff61541cc6c1962957758ba433c574b76f588d23 Author: Alexander Shishkin AuthorDate: Thu, 05 Dec 2019 17:28:52 +03:00 Committer: Peter Zijlstra CommitterDate: Tue, 17 Dec 2019 13:32:46 +01:00 perf/x86/intel/bts: Fix the use of page_private() Commit 8062382c8dbe2 ("perf/x86/intel/bts: Add BTS PMU driver") brought in a warning with the BTS buffer initialization that is easily tripped with (assuming KPTI is disabled): instantly throwing: > ------------[ cut here ]------------ > WARNING: CPU: 2 PID: 326 at arch/x86/events/intel/bts.c:86 bts_buffer_setup_aux+0x117/0x3d0 > Modules linked in: > CPU: 2 PID: 326 Comm: perf Not tainted 5.4.0-rc8-00291-gceb9e77324fa #904 > RIP: 0010:bts_buffer_setup_aux+0x117/0x3d0 > Call Trace: > rb_alloc_aux+0x339/0x550 > perf_mmap+0x607/0xc70 > mmap_region+0x76b/0xbd0 ... It appears to assume (for lost raisins) that PagePrivate() is set, while later it actually tests for PagePrivate() before using page_private(). Make it consistent and always check PagePrivate() before using page_private(). Fixes: 8062382c8dbe2 ("perf/x86/intel/bts: Add BTS PMU driver") Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Jiri Olsa Cc: Vince Weaver Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Link: https://lkml.kernel.org/r/20191205142853.28894-2-alexander.shishkin@linux.intel.com --- arch/x86/events/intel/bts.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c index 38de4a7..6a3b599 100644 --- a/arch/x86/events/intel/bts.c +++ b/arch/x86/events/intel/bts.c @@ -63,9 +63,17 @@ struct bts_buffer { static struct pmu bts_pmu; +static int buf_nr_pages(struct page *page) +{ + if (!PagePrivate(page)) + return 1; + + return 1 << page_private(page); +} + static size_t buf_size(struct page *page) { - return 1 << (PAGE_SHIFT + page_private(page)); + return buf_nr_pages(page) * PAGE_SIZE; } static void * @@ -83,9 +91,7 @@ bts_buffer_setup_aux(struct perf_event *event, void **pages, /* count all the high order buffers */ for (pg = 0, nbuf = 0; pg < nr_pages;) { page = virt_to_page(pages[pg]); - if (WARN_ON_ONCE(!PagePrivate(page) && nr_pages > 1)) - return NULL; - pg += 1 << page_private(page); + pg += buf_nr_pages(page); nbuf++; } @@ -109,7 +115,7 @@ bts_buffer_setup_aux(struct perf_event *event, void **pages, unsigned int __nr_pages; page = virt_to_page(pages[pg]); - __nr_pages = PagePrivate(page) ? 1 << page_private(page) : 1; + __nr_pages = buf_nr_pages(page); buf->buf[nbuf].page = page; buf->buf[nbuf].offset = offset; buf->buf[nbuf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0);