From patchwork Mon Aug 28 09:56:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maciej Wieczor-Retman X-Patchwork-Id: 13367753 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 EF3C1C83F17 for ; Mon, 28 Aug 2023 09:57:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230205AbjH1J4n (ORCPT ); Mon, 28 Aug 2023 05:56:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230267AbjH1J4i (ORCPT ); Mon, 28 Aug 2023 05:56:38 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7715B10C; Mon, 28 Aug 2023 02:56:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1693216595; x=1724752595; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=MwJO9kVVLHDRdzipUSYQDkBXMcwUOolgXO2rJ0yrZgg=; b=I7xjsNyCI1LrxfV61cHl47CfLyNfSF/gLXH7Us1zfVA0J34w9cq8B2yI XAyP+mUS7OagnprnqaDfDbtKrxG/REb9orUF/1Gsqh5ABPNbFarvMUrR+ CGkHa08ZnOsZ5ncEm5Gvy3+a1kQ0/S8iU5ZWJEBy2Hu3+96rv1nVjf1f+ SXBem4vnygKfxsKvdWcH+xPzsExyQ2hnTy94JSJ6yaBq/qq/wCxoGDi6g 1+sbxSU3jYYeIqsV7/NxYLgutbm6/GwJ7jzuZLOvk4ptpr78VaODdeTjR K/7zI5vOOhU7fcG+ROci/qGFkGNulj9knsxGZj5YcfPV2/kx/F+YMQia7 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10815"; a="365266311" X-IronPort-AV: E=Sophos;i="6.02,207,1688454000"; d="scan'208";a="365266311" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Aug 2023 02:56:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10815"; a="803650168" X-IronPort-AV: E=Sophos;i="6.02,207,1688454000"; d="scan'208";a="803650168" Received: from nwiklans-mobl.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.213.22.120]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Aug 2023 02:56:19 -0700 From: "Wieczor-Retman, Maciej" To: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, fenghua.yu@intel.com, reinette.chatre@intel.com Cc: ilpo.jarvinen@linux.intel.com Subject: [PATCH v2 1/2] selftests/resctrl: Fix schemata write error check Date: Mon, 28 Aug 2023 11:56:07 +0200 Message-ID: <6c263fdd2b09060e667d179be13ce8f989821673.1693213468.git.maciej.wieczor-retman@intel.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Writing bitmasks to the schemata can fail when the bitmask doesn't adhere to some constraints defined by what a particular CPU supports. Some example of constraints are max length or having contiguous bits. The driver should properly return errors when any rule concerning bitmask format is broken. Resctrl FS returns error codes from fprintf() only when fclose() is called. Current error checking scheme allows invalid bitmasks to be written into schemata file and the selftest doesn't notice because the fclose() error code isn't checked. Substitute fopen(), flose() and fprintf() with open(), close() and write() to avoid error code buffering between fprintf() and fclose(). Add newline to the end of the schema string so it satisfies rdt schemata writing requirements. Remove newline character from the schemat string after writing it to the schemata file so it prints correctly before function return. Pass the string generated with strerror() to the "reason" buffer so the error message is more verbose. Extend "reason" buffer so it can hold longer messages. Changelog v2: - Rewrite patch message. - Double "reason" buffer size to fit longer error explanation. - Redo file interactions with syscalls instead of stdio functions. Signed-off-by: Wieczor-Retman, Maciej --- tools/testing/selftests/resctrl/resctrlfs.c | 24 +++++++++++---------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index bd36ee206602..0f9644e5a25e 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -488,9 +488,8 @@ int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char *mongrp, */ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val) { - char controlgroup[1024], schema[1024], reason[64]; - int resource_id, ret = 0; - FILE *fp; + char controlgroup[1024], schema[1024], reason[128]; + int resource_id, fp, ret = 0; if (strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) && strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) && @@ -518,27 +517,30 @@ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val) if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR)) || !strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) - sprintf(schema, "%s%d%c%s", "L3:", resource_id, '=', schemata); + snprintf(schema, sizeof(schema), "%s%d%c%s\n", "L3:", + resource_id, '=', schemata); if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) || !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) - sprintf(schema, "%s%d%c%s", "MB:", resource_id, '=', schemata); + snprintf(schema, sizeof(schema), "%s%d%c%s\n", "MB:", + resource_id, '=', schemata); - fp = fopen(controlgroup, "w"); + fp = open(controlgroup, O_WRONLY); if (!fp) { sprintf(reason, "Failed to open control group"); ret = -1; goto out; } - - if (fprintf(fp, "%s\n", schema) < 0) { - sprintf(reason, "Failed to write schemata in control group"); - fclose(fp); + if (write(fp, schema, strlen(schema)) < 0) { + snprintf(reason, sizeof(reason), + "write() failed : %s", strerror(errno)); + close(fp); ret = -1; goto out; } - fclose(fp); + close(fp); + schema[strcspn(schema, "\n")] = 0; out: ksft_print_msg("Write schema \"%s\" to resctrl FS%s%s\n",