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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2F35C6FA82 for ; Thu, 22 Sep 2022 11:40:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230482AbiIVLkN (ORCPT ); Thu, 22 Sep 2022 07:40:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbiIVLkK (ORCPT ); Thu, 22 Sep 2022 07:40:10 -0400 X-Greylist: delayed 442 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 22 Sep 2022 04:40:07 PDT Received: from smtp-out.xnet.cz (smtp-out.xnet.cz [178.217.244.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4313796A1 for ; Thu, 22 Sep 2022 04:40:07 -0700 (PDT) Received: from meh.true.cz (meh.true.cz [108.61.167.218]) (Authenticated sender: petr@true.cz) by smtp-out.xnet.cz (Postfix) with ESMTPSA id 82EF818878; Thu, 22 Sep 2022 13:32:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=true.cz; s=xnet; t=1663846363; bh=dyFs+ziM8uDY0R3f2ueo4RCrj2lCmCsMBiBeN+xFTfs=; h=Date:From:To:Cc:Subject:Reply-To; b=H4V5lMN9ekH+80kn4j+ND311olRdGOftlcoK6ZIgfzmXmEoXUw9SVdGpuSw3AuE9H 8q/w28VklfC2FPhL0sPmh4oFg8uxbfBFd1Z+FkHkuI7rcSznPOTyqW9ByFKdTXOXrY Eq4lbD6mwn3/4evg3xPRtC/zuxpe0w4+YvPmP1hM= Received: from localhost (meh.true.cz [local]) by meh.true.cz (OpenSMTPD) with ESMTPA id d44b4f97; Thu, 22 Sep 2022 13:32:17 +0200 (CEST) Date: Thu, 22 Sep 2022 13:32:17 +0200 From: Petr =?utf-8?Q?=C5=A0tetiar?= To: linux-kernel@vger.kernel.org Cc: pauld@redhat.com, yury.norov@gmail.com, rafael@kernel.org, Greg Kroah-Hartman Subject: aarch64 5.15.68 regression in topology/thread_siblings (huge file size and no content) Message-ID: <20220922113217.GA90426@meh.true.cz> Reply-To: Petr =?utf-8?Q?=C5=A0tetiar?= MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, we've got a recent bug report[1], that lscpu segfaults on aarch64 board running 5.15.y kernel. It is working fine on 5.10.y kernel. I've tracked it down[2] to the issue with `topology/thread_siblings` which apart from very strange file size returns empty content. I assume, that it's somehow related to the changes done in commit bb9ec13d156e ("topology: use bin_attribute to break the size limitation of cpumap ABI"), but I didn't tried to revert it yet to verify it. Kernel 5.15.68: root@OpenWrt:/# uname -a Linux OpenWrt 5.15.68 #0 SMP Wed Sep 21 05:54:21 2022 aarch64 GNU/Linux root@OpenWrt:/# find /sys -name thread_siblings -exec ls -al {} \; -r--r--r-- 1 root root 18446744073709551615 Sep 22 08:37 /sys/devices/system/cpu/cpu1/topology/thread_siblings -r--r--r-- 1 root root 18446744073709551615 Sep 22 08:37 /sys/devices/system/cpu/cpu0/topology/thread_siblings root@OpenWrt:/# find /sys -name thread_siblings -exec cat {} \; root@OpenWrt:/# Kernel 5.10.138: root@OpenWrt:/# uname -a Linux OpenWrt 5.10.138 #0 SMP Sat Sep 3 02:55:34 2022 aarch64 GNU/Linux root@OpenWrt:/# find /sys -name thread_siblings -exec cat {} \; 2 1 root@OpenWrt:/# find /sys -name thread_siblings -exec ls -al {} \; -r--r--r-- 1 root root 4096 Sep 22 11:12 /sys/devices/system/cpu/cpu1/topology/thread_siblings -r--r--r-- 1 root root 4096 Sep 22 11:12 /sys/devices/system/cpu/cpu0/topology/thread_siblings 1. https://github.com/openwrt/openwrt/issues/10737 2. https://github.com/util-linux/util-linux/pull/1821 Cheers, Petr