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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 01277C61DC2 for ; Wed, 26 Aug 2026 08:26:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6WsTGWxVnSc0KtrZO8pZRE2QxEimJ5VHS+fEe/s67Mc=; b=KqiYTgFf4OlXyd0AMNQb7ry5cM Uwh8Ep7llqSO7luVjhLMQB3/81LuQH7Y8ZTot6edBrhlONssTEYos1B02JsVMwFYsRIpMcgj5WE75 dGEFfmD3hKaFsZQ7vWdTg1v+9nk8R2JtxV6+Z8sQ1XC+bOoAhOXig0Ke4GTbLnn0tpNnOG6uLjQx4 zIa9zt8sBlp8MY9I0AvDrxfj/vJP0WcUyi7d/pQ2gDtOI+OiNDACT93ss+1WGXE6W1FPPdcauL9Hq rwwoT/UFy63wCSrAAjb7fDT7A+rp+UpUGk6znquJgu1Xgc59mgcEv3uhOvwzZso+snQdkmyjdmFf2 zPAJaV2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wz8y7-000000025gw-18W0; Wed, 26 Aug 2026 08:26:47 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wz8y4-000000025gH-0dkM for linux-arm-kernel@lists.infradead.org; Wed, 26 Aug 2026 08:26:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 86300176A; Wed, 26 Aug 2026 01:26:39 -0700 (PDT) Received: from [192.168.7.252] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BFEB73F7D8; Wed, 26 Aug 2026 01:26:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1787732803; bh=ffC2F63al/Ef4j0Fsqvq/nU7950u0pWRTQY2EH1H4VU=; h=Date:Subject:To:References:From:In-Reply-To:From; b=ZC8GM8fDR7M8D3wHsts2j8AaJEydieWRKVP/M3m4CnifF1ZDE6S0lE2RAVi9JFwJ0 /ccpoUH4fpT7dy1sqWgVzFl5uGlz5Ksi/9s37MKsx8h9C4qLYM42+QDKNqKNStIrPS ZKekhtKJHE1MtkX2XZtkNmQ9bf8aXbKJ4zHErBUc= Message-ID: <30d29c7a-3d66-498f-9777-8dadbb0a4584@arm.com> Date: Wed, 26 Aug 2026 09:26:40 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/4] selftests/arm64: Treat KSM merge_across_nodes as optional To: Muhammad Usama Anjum , Catalin Marinas , Will Deacon , Mark Rutland , Shuah Khan , Andrey Konovalov , Andrew Morton , Amit Daniel Kachhap , Yeoreum Yun , Mark Brown , open list , "moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)" , "open list:KERNEL SELFTEST FRAMEWORK" References: <20260825111929.2882324-1-usama.anjum@arm.com> <20260825111929.2882324-3-usama.anjum@arm.com> Content-Language: en-GB From: Vincenzo Frascino In-Reply-To: <20260825111929.2882324-3-usama.anjum@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260826_012644_236811_A045E6F6 X-CRM114-Status: GOOD ( 12.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 25/08/2026 12:18, Muhammad Usama Anjum wrote: > The MTE KSM test requires write access to KSM sysfs but does not check > that it is running as root. It also unconditionally saves, enables and > restores the merge_across_nodes attribute. The kernel only creates this > attribute when CONFIG_NUMA=y, so a non-NUMA kernel prints the following > message three times even though every KSM subtest passes: > > # ERR: missing /sys/kernel/mm/ksm/merge_across_nodes > > Skip the test when it is not running as root. Check that the optional > attribute is readable and writable, treating ENOENT as its expected > absence on non-NUMA kernels and skipping the test for other access > failures. Only save, enable and restore the attribute when it is > available. > > Check MTE availability before the privilege and sysfs checks so systems > without MTE retain the existing feature-unavailable skip result. > > This preserves the existing behavior on NUMA kernels without requiring > NUMA or reducing KSM coverage on single-node systems. > > Fixes: f981d8fa2646 ("kselftest/arm64: Verify KSM page merge for MTE pages") > Signed-off-by: Muhammad Usama Anjum Reviewed-by: Vincenzo Frascino ...