From nobody Mon Feb 9 03:11:19 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3239D69D01; Tue, 12 Mar 2024 08:05:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710230729; cv=none; b=Ar1wNXfJexzNVgSmUqmKN4Kyqd92aMatGToeAwCd88Vs+yzDxCp6s5rBxVX7j6WyaWZIKzpvHwqYR3R0PGuUfwTo9sYZlUf9W2jY/rnK5AQNEMx9WS28Dh+DLY4I48hfMxFL7x5Uap/NEZmET6fHlTP+BVveMArtbFNF/nl87zg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710230729; c=relaxed/simple; bh=ZGEVlJ/kaJVd0E8jYAG2DeF+zHotxbyxow0UORgWJEs=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=GF0hUMxQeFfIyz2djOibgGlFp43b20llN+oa1idX28hCo+zqcahS7YFqjcrsSNK+qKJmyWz2FvK9fzUGqpSMTt5pjo7YrQSWSdzmxGtwhA9wJDmsX1UglA/h22urcIXB/7DURip3b3UhMDh1QtzRVqD7C9M593OWzLkSr3X5zAc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=nzZN5mtv; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="nzZN5mtv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1710230728; x=1741766728; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=ZGEVlJ/kaJVd0E8jYAG2DeF+zHotxbyxow0UORgWJEs=; b=nzZN5mtvVWMMfEjLfqLh5rSSt61Sk3cMw76OFkZLauotveCBa84RELz3 8x/n01blZAK2tgxVrGPfLMdBViiCj3Vl3BPlEkTiSEO9J4nIAeoZvaGCg /dDABe5qoDiWt4GwkS5WtC9shD/s4+hXOqqbUshj2ZQxSLhx6QP/4KNYo 4Fe2um9ctgKQWJc1wsSXxDQ7tM+9MQ3RpsbuDY3RIKcZ1bvbjH5kqA1NF lFr1WDqCy49QKP3Ni7kqfOo6rjx4Y1JfEDX3mB+5hC+qigQ+kC3MeFQVq iTAfROEgHxbrynoz4sihMlMuy+OH7YqOjwHfPc7H8CplsG1OTnzlHobqG A==; X-IronPort-AV: E=McAfee;i="6600,9927,11010"; a="5112973" X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="5112973" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2024 01:05:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="34631465" Received: from qzhang4-desk.sh.intel.com (HELO localhost) ([10.239.147.49]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2024 01:05:24 -0700 From: Qiang Zhang To: Andrew Morton , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Qiang Zhang , Stable@vger.kernel.org Subject: [PATCH] memtest: use {READ,WRITE}_ONCE in memory scanning Date: Tue, 12 Mar 2024 16:04:23 +0800 Message-Id: <20240312080422.691222-1-qiang4.zhang@intel.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" memtest failed to find bad memory when compiled with clang. So use {WRITE,READ}_ONCE to access memory to avoid compiler over optimization. Cc: Signed-off-by: Qiang Zhang --- mm/memtest.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memtest.c b/mm/memtest.c index 32f3e9dda837..c2c609c39119 100644 --- a/mm/memtest.c +++ b/mm/memtest.c @@ -51,10 +51,10 @@ static void __init memtest(u64 pattern, phys_addr_t sta= rt_phys, phys_addr_t size last_bad =3D 0; =20 for (p =3D start; p < end; p++) - *p =3D pattern; + WRITE_ONCE(*p, pattern); =20 for (p =3D start; p < end; p++, start_phys_aligned +=3D incr) { - if (*p =3D=3D pattern) + if (READ_ONCE(*p) =3D=3D pattern) continue; if (start_phys_aligned =3D=3D last_bad + incr) { last_bad +=3D incr; --=20 2.39.2