From patchwork Wed Jan 29 11:32:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: thermal-bot for Julien Panis X-Patchwork-Id: 232417 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=-9.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, URIBL_DBL_ABUSE_MALW 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 0F2B2C33CB2 for ; Wed, 29 Jan 2020 11:33:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD53420716 for ; Wed, 29 Jan 2020 11:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726591AbgA2LdG (ORCPT ); Wed, 29 Jan 2020 06:33:06 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:51053 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbgA2LdF (ORCPT ); Wed, 29 Jan 2020 06:33:05 -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 1iwlaa-0007kN-Mo; Wed, 29 Jan 2020 12:32:56 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 578D01C1C19; Wed, 29 Jan 2020 12:32:56 +0100 (CET) Date: Wed, 29 Jan 2020 11:32:56 -0000 From: "tip-bot2 for Song Liu" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/urgent] perf/core: Fix mlock accounting in perf_mmap() Cc: Alexander Shishkin , Song Liu , "Peter Zijlstra (Intel)" , Ingo Molnar , , x86 , LKML In-Reply-To: <20200123181146.2238074-1-songliubraving@fb.com> References: <20200123181146.2238074-1-songliubraving@fb.com> MIME-Version: 1.0 Message-ID: <158029757616.396.9494045381575919767.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails X-Linutronix-Spam-Score: 1.5 X-Linutronix-Spam-Level: + X-Linutronix-Spam-Status: No , 1.5 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001, URIBL_DBL_ABUSE_MALW=2.5 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the perf/urgent branch of tip: Commit-ID: 003461559ef7a9bd0239bae35a22ad8924d6e9ad Gitweb: https://git.kernel.org/tip/003461559ef7a9bd0239bae35a22ad8924d6e9ad Author: Song Liu AuthorDate: Thu, 23 Jan 2020 10:11:46 -08:00 Committer: Ingo Molnar CommitterDate: Tue, 28 Jan 2020 21:20:18 +01:00 perf/core: Fix mlock accounting in perf_mmap() Decreasing sysctl_perf_event_mlock between two consecutive perf_mmap()s of a perf ring buffer may lead to an integer underflow in locked memory accounting. This may lead to the undesired behaviors, such as failures in BPF map creation. Address this by adjusting the accounting logic to take into account the possibility that the amount of already locked memory may exceed the current limit. Fixes: c4b75479741c ("perf/core: Make the mlock accounting simple again") Suggested-by: Alexander Shishkin Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Acked-by: Alexander Shishkin Link: https://lkml.kernel.org/r/20200123181146.2238074-1-songliubraving@fb.com --- kernel/events/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 2173c23..2d9aeba 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5916,7 +5916,15 @@ accounting: */ user_lock_limit *= num_online_cpus(); - user_locked = atomic_long_read(&user->locked_vm) + user_extra; + user_locked = atomic_long_read(&user->locked_vm); + + /* + * sysctl_perf_event_mlock may have changed, so that + * user->locked_vm > user_lock_limit + */ + if (user_locked > user_lock_limit) + user_locked = user_lock_limit; + user_locked += user_extra; if (user_locked > user_lock_limit) { /*