From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0EDBE481D1; Mon, 1 Apr 2024 16:44:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711989870; cv=none; b=BTIqv6t4x2bUpJdU5Qg/eUXeT8u+OCJACwZ9UR1DQ+JyfbA0GHCcnzsA9sApJ98NfefYzSurtkBNLWLJ1xKSEOllS4nBv4z+L5CrOxX0dlrHKYPrtAj/axreA6BAGx77+Jw71zHy0b/8yrVxijqGP3NFFOdC7NVjv59EbZhT2Pw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711989870; c=relaxed/simple; bh=VZAzM+K0xXEju8eXJ1Rzstc/mFstNdkOTz7zopzJ18w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UQE4BuIoHt+GIYyZefQ/8Kj+ayhwTRW7g/uI8bFkhInw/uDrbqbTfm3kLcZIo2dJ6D7cuNKQ2B795eUj9561OOUZywXOUpppRV56xnlfRWMHu9BILgYIznMOhDmhZW/acdO8BpSqmG8z2O5jS16MWnJktqJMpEiagsbPM1sfZIM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zDGCigcd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zDGCigcd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7167BC433C7; Mon, 1 Apr 2024 16:44:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1711989869; bh=VZAzM+K0xXEju8eXJ1Rzstc/mFstNdkOTz7zopzJ18w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zDGCigcdk3NF7YagRIBPKYIaWkamANJLNcUKjgs7LAxbZ9WLdWikdxeyELXZyYCh7 iKWdWYSPt57S9nCq5VGbfLDodHTCvbBo6Ki4lzNoWnXOuAJwFUCItXmb4QeIH+Lc83 4U9/6W6slScW2VwT1RKTC1h93L00Azs69zFnoVuk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qiang Zhang , Bill Wendling , Justin Stitt , Nathan Chancellor , Nick Desaulniers , Andrew Morton , Sasha Levin Subject: [PATCH 6.6 150/396] memtest: use {READ,WRITE}_ONCE in memory scanning Date: Mon, 1 Apr 2024 17:43:19 +0200 Message-ID: <20240401152552.417309733@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240401152547.867452742@linuxfoundation.org> References: <20240401152547.867452742@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qiang Zhang [ Upstream commit 82634d7e24271698e50a3ec811e5f50de790a65f ] memtest failed to find bad memory when compiled with clang. So use {WRITE,READ}_ONCE to access memory to avoid compiler over optimization. Link: https://lkml.kernel.org/r/20240312080422.691222-1-qiang4.zhang@intel.com Signed-off-by: Qiang Zhang Cc: Bill Wendling Cc: Justin Stitt Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- mm/memtest.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memtest.c b/mm/memtest.c index 32f3e9dda8370..c2c609c391199 100644 --- a/mm/memtest.c +++ b/mm/memtest.c @@ -51,10 +51,10 @@ static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size last_bad = 0; for (p = start; p < end; p++) - *p = pattern; + WRITE_ONCE(*p, pattern); for (p = start; p < end; p++, start_phys_aligned += incr) { - if (*p == pattern) + if (READ_ONCE(*p) == pattern) continue; if (start_phys_aligned == last_bad + incr) { last_bad += incr; -- 2.43.0