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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 788D5C433E3 for ; Mon, 13 Jul 2020 18:32:08 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 308192075D for ; Mon, 13 Jul 2020 18:32:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 308192075D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4B5C122QbFzDqZW for ; Tue, 14 Jul 2020 04:32:06 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=cmarinas@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4B5Bvy29ydzDqLK for ; Tue, 14 Jul 2020 04:27:41 +1000 (AEST) Received: from gaia (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7D6DB206F5; Mon, 13 Jul 2020 18:27:38 +0000 (UTC) Date: Mon, 13 Jul 2020 19:27:36 +0100 From: Catalin Marinas To: Paul Menzel Subject: Re: /sys/kernel/debug/kmemleak empty despite kmemleak reports Message-ID: <20200713182735.GH15829@gaia> References: <070dd6b7-1ee6-8090-8973-1eb0240f6948@molgen.mpg.de> <20200709175705.GD6579@gaia> <276e4bce-3e21-8020-9a1c-729a6cafcdd3@molgen.mpg.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <276e4bce-3e21-8020-9a1c-729a6cafcdd3@molgen.mpg.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jul 09, 2020 at 11:08:52PM +0200, Paul Menzel wrote: > Am 09.07.20 um 19:57 schrieb Catalin Marinas: > > On Thu, Jul 09, 2020 at 04:37:10PM +0200, Paul Menzel wrote: > > > Despite Linux 5.8-rc4 reporting memory leaks on the IBM POWER 8 S822LC, the > > > file does not contain more information. > > > > > > > $ dmesg > > > > […] > [48662.953323] perf: interrupt took too long (2570 > 2500), lowering kernel.perf_event_max_sample_rate to 77750 > > > > [48854.810636] perf: interrupt took too long (3216 > 3212), lowering kernel.perf_event_max_sample_rate to 62000 > > > > [52300.044518] perf: interrupt took too long (4244 > 4020), lowering kernel.perf_event_max_sample_rate to 47000 > > > > [52751.373083] perf: interrupt took too long (5373 > 5305), lowering kernel.perf_event_max_sample_rate to 37000 > > > > [53354.000363] perf: interrupt took too long (6793 > 6716), lowering kernel.perf_event_max_sample_rate to 29250 > > > > [53850.215606] perf: interrupt took too long (8672 > 8491), lowering kernel.perf_event_max_sample_rate to 23000 > > > > [57542.266099] perf: interrupt took too long (10940 > 10840), lowering kernel.perf_event_max_sample_rate to 18250 > > > > [57559.645404] perf: interrupt took too long (13714 > 13675), lowering kernel.perf_event_max_sample_rate to 14500 > > > > [61608.697728] Can't find PMC that caused IRQ > > > > [71774.463111] kmemleak: 12 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > > > > [92372.044785] process '@/usr/bin/gnatmake-5' started with executable stack > > > > [92849.380672] FS-Cache: Loaded > > > > [92849.417269] FS-Cache: Netfs 'nfs' registered for caching > > > > [92849.595974] NFS: Registering the id_resolver key type > > > > [92849.596000] Key type id_resolver registered > > > > [92849.596000] Key type id_legacy registered > > > > [101808.079143] kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > > > > [106904.323471] Can't find PMC that caused IRQ > > > > [129416.391456] kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > > > > [158171.604221] kmemleak: 34 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > > > > $ sudo cat /sys/kernel/debug/kmemleak > > > > When they are no longer present, they are most likely false positives. > > How can this be? Shouldn’t the false positive also be logged in > `/sys/kernel/debug/kmemleak`? Sorry, I wasn't clear. It can be a transient false positive. At a subsequent scan, kmemleak found pointer referring the previously reported objects and no longer shows them. > > Was this triggered during boot? Or under some workload? > > From the timestamps it looks like under some load. Was it during boot? I put a delay of 60s to avoid this but, depending on the platform, it can still trigger. -- Catalin