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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 284BBC2D0CE for ; Fri, 24 Jan 2020 09:26:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00FFD20838 for ; Fri, 24 Jan 2020 09:26:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730540AbgAXJZ7 (ORCPT ); Fri, 24 Jan 2020 04:25:59 -0500 Received: from mga05.intel.com ([192.55.52.43]:14069 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729593AbgAXJZ7 (ORCPT ); Fri, 24 Jan 2020 04:25:59 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2020 01:25:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,357,1574150400"; d="scan'208";a="260181466" Received: from um.fi.intel.com (HELO um) ([10.237.72.57]) by fmsmga002.fm.intel.com with ESMTP; 24 Jan 2020 01:25:56 -0800 From: Alexander Shishkin To: Song Liu , linux-kernel@vger.kernel.org Cc: kernel-team@fb.com, Song Liu , Arnaldo Carvalho de Melo , Jiri Olsa , Peter Zijlstra , alexander.shishkin@linux.intel.com Subject: Re: [PATCH v3] perf/core: fix mlock accounting in perf_mmap() In-Reply-To: <20200123181146.2238074-1-songliubraving@fb.com> References: <20200123181146.2238074-1-songliubraving@fb.com> Date: Fri, 24 Jan 2020 11:25:55 +0200 Message-ID: <87zhed9pek.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Song Liu writes: > Eecreasing sysctl_perf_event_mlock between two consecutive perf_mmap()s of Typo: "Decreasing". > 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") > Signed-off-by: Song Liu > Suggested-by: Alexander Shishkin > Cc: Alexander Shishkin > Cc: Arnaldo Carvalho de Melo > Cc: Jiri Olsa > Cc: Peter Zijlstra Other than that, Acked-by: Alexander Shishkin Thanks, -- Alex