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 35100C43334 for ; Wed, 15 Jun 2022 22:06:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241445AbiFOWGu (ORCPT ); Wed, 15 Jun 2022 18:06:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238652AbiFOWGt (ORCPT ); Wed, 15 Jun 2022 18:06:49 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B23C563A5; Wed, 15 Jun 2022 15:06:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655330808; x=1686866808; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=1F3Ip+Ag85q874qUWiUpOUFx42ubled3GFsealoyUEY=; b=jLUJsN6ZtepAXju18mabDHtlsOTrwJKoAAW2mOQN2BTvL6sUwJEBtQoK VwUfv8n0XgmCPfVidAcYfvTeksy0A+wSwMeWhYpTnpZEpG0rH3tEiMtLD /h/5V4UBSgnWoJWBcFUirJv4EGakYOpqAlzRU1sxeIloqmR+r+JoxWrmP bCdNhFfIdttJSeXN2L70hUhnV395ufuwuKcHVeTxB67eagtVpFPHsOw7E TB7QDdd0S2sbyWa+cVg7Lqj/9Ui1fkeIbz7BEY8t0qu2xu6Ue/QnFuG5D 93wBHdZIpT/mrnkxzwXjUbzgJqzRKqfcR7JegijcfjouYpmfF+3z8OYex A==; X-IronPort-AV: E=McAfee;i="6400,9594,10379"; a="259573532" X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="259573532" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 15:06:48 -0700 X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="583398809" Received: from agluck-desk3.sc.intel.com ([172.25.222.78]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 15:06:47 -0700 Date: Wed, 15 Jun 2022 15:06:46 -0700 From: "Luck, Tony" To: "Rafael J. Wysocki" Cc: Darren Hart , LKML , Linux ACPI , Len Brown , James Morse , Borislav Petkov , Doug Rady Subject: Re: [PATCH] ACPI/APEI: Limit printable size of BERT table data Message-ID: References: <43dfaba0646d498fe94c1a8479b812346133f438.1646765290.git.darren@os.amperecomputing.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wed, Mar 09, 2022 at 07:42:26PM +0100, Rafael J. Wysocki wrote: > On Tue, Mar 8, 2022 at 7:51 PM Darren Hart > Not that I have a particularly strong opinion here, but this looks > reasonable to me, so I've queued it up for 5.18. > > APEI reviewers, please chime in if you disagree with the above. It looked reasonable to me when I skimmed it in March. But the reality check now needs cashing because some validation team here is complaining that they don't see any errors printed from their BERT tests. :-( So I looked again. This test inside the loop seems bogus: if (region_len < ACPI_BERT_PRINT_MAX_LEN) { because "region_len" isn't updated inside the loop. If it is too big then it will prevent Linux from printing any/all of the records in the BERT table (and the test could have been done before the loop). Maybe below patch is better? It avoids printing individual CPER records that are too large (checking estatus_len instead of region_len). I also added a limit to how many records to print (I randomly picked "5" as the limit ... the specific failing test only want to print one). -Tony [I will write up a proper commit message and add a Signed-off-by if this looks to be a reasonable direction] diff --git a/drivers/acpi/apei/bert.c b/drivers/acpi/apei/bert.c index 598fd19b65fa..4e894a728c02 100644 --- a/drivers/acpi/apei/bert.c +++ b/drivers/acpi/apei/bert.c @@ -29,6 +29,8 @@ #undef pr_fmt #define pr_fmt(fmt) "BERT: " fmt + +#define ACPI_BERT_PRINT_MAX_RECORDS 5 #define ACPI_BERT_PRINT_MAX_LEN 1024 static int bert_disable; @@ -39,6 +41,7 @@ static void __init bert_print_all(struct acpi_bert_region *region, struct acpi_hest_generic_status *estatus = (struct acpi_hest_generic_status *)region; int remain = region_len; + int ncper = 0, skipped = 0; u32 estatus_len; while (remain >= sizeof(struct acpi_bert_region)) { @@ -46,24 +49,23 @@ static void __init bert_print_all(struct acpi_bert_region *region, if (remain < estatus_len) { pr_err(FW_BUG "Truncated status block (length: %u).\n", estatus_len); - return; + break; } /* No more error records. */ if (!estatus->block_status) - return; + break; if (cper_estatus_check(estatus)) { pr_err(FW_BUG "Invalid error record.\n"); - return; + break; } pr_info_once("Error records from previous boot:\n"); - if (region_len < ACPI_BERT_PRINT_MAX_LEN) + if (ncper++ < ACPI_BERT_PRINT_MAX_RECORDS && estatus_len < ACPI_BERT_PRINT_MAX_LEN) cper_estatus_print(KERN_INFO HW_ERR, estatus); else - pr_info_once("Max print length exceeded, table data is available at:\n" - "/sys/firmware/acpi/tables/data/BERT"); + skipped++; /* * Because the boot error source is "one-time polled" type, @@ -75,6 +77,9 @@ static void __init bert_print_all(struct acpi_bert_region *region, estatus = (void *)estatus + estatus_len; remain -= estatus_len; } + if (skipped) + pr_info("Skipped %d error records, full table data is available at:\n" + "/sys/firmware/acpi/tables/data/BERT", skipped); } static int __init setup_bert_disable(char *str)