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=-5.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 0A1C6C54FD0 for ; Mon, 27 Apr 2020 07:02:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC6C32075B for ; Mon, 27 Apr 2020 07:02:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b="XsGDxGSA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726625AbgD0HCF (ORCPT ); Mon, 27 Apr 2020 03:02:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726221AbgD0HCF (ORCPT ); Mon, 27 Apr 2020 03:02:05 -0400 X-Greylist: delayed 86010 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 27 Apr 2020 00:02:05 PDT Received: from dvalin.narfation.org (dvalin.narfation.org [IPv6:2a00:17d8:100::8b1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26DECC061A0F for ; Mon, 27 Apr 2020 00:02:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1587970919; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KbvoomzfamrUKNn59kmZAaB2OHNvjnwBMb+jI5NKQP0=; b=XsGDxGSAPBbqFwVqwRf2WKSF0Ki301aVcMzm54qPyJSrsY5Xk5q6yUSVemTM9OIgETS8wH /1hJQGpdwBEh+0Pq1qwChOYULqWgkZH10O7aUcqYbp1XjKkl8JAqkJBsufEH+SAhRLOlVU s53eFkNocD10V31MqdjWyFSqPvpiRvs= From: Sven Eckelmann To: Sasha Levin Cc: stable@vger.kernel.org, Vlastimil Babka , Kees Cook , Daniel Micay , Eric Dumazet , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Matthias Schiffer , Andrew Morton , Linus Torvalds Subject: Re: [PATCH 4.14] mm, slub: restore the original intention of prefetch_freepointer() Date: Mon, 27 Apr 2020 09:01:56 +0200 Message-ID: <11030934.sCltEm0ppq@bentobox> In-Reply-To: <20200426231426.GM13035@sasha-vm> References: <20200426070617.14575-1-sven@narfation.org> <20200426231426.GM13035@sasha-vm> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart7321197.xugn6qQKx4"; micalg="pgp-sha512"; protocol="application/pgp-signature" Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org --nextPart7321197.xugn6qQKx4 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Monday, 27 April 2020 01:14:26 CEST Sasha Levin wrote: > On Sun, Apr 26, 2020 at 09:06:17AM +0200, Sven Eckelmann wrote: > >From: Vlastimil Babka > > > >commit 0882ff9190e3bc51e2d78c3aadd7c690eeaa91d5 upstream. [...] > >--- > >The original problem is explained in the patch description as > >performance problem. And maybe this could also be one reason why it was > >never submitted for a stable kernel. > > > >But tests on mips ath79 (OpenWrt ar71xx target) showed that it most likely > >related to "random" data bus errors. At least applying this patch seemed to > >have solved it for Matthias Schiffer and > >some other persons who where debugging/testing this problem with him. > > > >More details about it can be found in > >https://github.com/freifunk-gluon/gluon/issues/1982 > > Interesting... I wonder why this issue has started only now. Unfortunately, I don't know the details. So I (actually we) would love to get some feedback from the slub experts. Not that there is another problem which we just don't grasp yet. Just some background information about the "why" from freifunk-gluon's perspective: OpenWrt 19.07 was released (despite its name) at the beginning of 2020. And it was the first release using kernel 4.14 on the most used target: ar71xx (ath79). The wireless community network firmware projects (freifunk-gluon in this example) updated their frameworks to this OpenWrt release in the last months and just now started to roll it out on their networks. And while the wireless community networks around here usually don't track the connected clients, the health of the APs is often tracked on some central system. And some people then just noticed a sudden spike of reboots on their APs. Since ar71xx is (often) the most used architecture at the moment, this could be spotted rather easily if you spend some time looking at graphs. Kind regards, Sven --nextPart7321197.xugn6qQKx4 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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