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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09924C433E0 for ; Wed, 17 Feb 2021 10:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C66B764DA1 for ; Wed, 17 Feb 2021 10:27:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232366AbhBQK1a (ORCPT ); Wed, 17 Feb 2021 05:27:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:25892 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230492AbhBQK0k (ORCPT ); Wed, 17 Feb 2021 05:26:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613557510; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7D9yQe5KSdsAiSzGvNRFKBC83KBbNru7nLK5pMb4JFI=; b=O+QBmyCHRhrPnGewB+ZQMcUQq8u4tmI9/5oEuz2ZgXi60zGG9IzYEn/K9n7Gmr8RtJZsQM xP2ndwKF3aC/Dj4pgvPTzerWR9lUWmikTTTCEYxMQw8Of6XCAim1g8e+CI8G6Z8HJWAVxO 8FqeaUYJpRLEzz+tYDXaoYyDRc1iwao= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-424-8kjSWx8BNqiDypGfMhtx3g-1; Wed, 17 Feb 2021 05:25:05 -0500 X-MC-Unique: 8kjSWx8BNqiDypGfMhtx3g-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4BF2B192D785; Wed, 17 Feb 2021 10:25:04 +0000 (UTC) Received: from x1.localdomain (ovpn-115-224.ams2.redhat.com [10.36.115.224]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA0D77086D; Wed, 17 Feb 2021 10:25:02 +0000 (UTC) From: Hans de Goede To: Eric Piel , Arnd Bergmann , Greg Kroah-Hartman Cc: Hans de Goede , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/3] misc: lis3lv02d: Fix false-positive WARN on various HP models Date: Wed, 17 Feb 2021 11:24:59 +0100 Message-Id: <20210217102501.31758-1-hdegoede@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Before this commit lis3lv02d_get_pwron_wait() had a WARN_ONCE() to catch a potential divide by 0. WARN macros should only be used to catch internal kernel bugs and that is not the case here. We have been receiving a lot of bug reports about kernel backtraces caused by this WARN. The div value being checked comes from the lis3->odrs[] array. Which is sized to be a power-of-2 matching the number of bits in lis3->odr_mask. The only lis3 model where this array is not entirely filled with non zero values. IOW the only model where we can hit the div == 0 check is the 3dc ("8 bits 3DC sensor") model: int lis3_3dc_rates[16] = {0, 1, 10, 25, 50, 100, 200, 400, 1600, 5000}; Note the 0 value at index 0, according to the datasheet an odr index of 0 means "Power-down mode". HP typically uses a lis3 accelerometer for HDD fall protection. What I believe is happening here is that on newer HP devices, which only contain a SDD, the BIOS is leaving the lis3 device powered-down since it is not used for HDD fall protection. Note that the lis3_3dc_rates array initializer only specifies 10 values, which matches the datasheet. So it also contains 6 zero values at the end. Replace the WARN with a normal check, which treats an odr index of 0 as power-down and uses a normal dev_err() to report the error in case odr index point past the initialized part of the array. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=785814 BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1817027 BugLink: https://bugs.centos.org/view.php?id=10720 Fixes: 1510dd5954be ("lis3lv02d: avoid divide by zero due to unchecked") Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede --- drivers/misc/lis3lv02d/lis3lv02d.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/misc/lis3lv02d/lis3lv02d.c b/drivers/misc/lis3lv02d/lis3lv02d.c index dd65cedf3b12..9d14bf444481 100644 --- a/drivers/misc/lis3lv02d/lis3lv02d.c +++ b/drivers/misc/lis3lv02d/lis3lv02d.c @@ -208,7 +208,7 @@ static int lis3_3dc_rates[16] = {0, 1, 10, 25, 50, 100, 200, 400, 1600, 5000}; static int lis3_3dlh_rates[4] = {50, 100, 400, 1000}; /* ODR is Output Data Rate */ -static int lis3lv02d_get_odr(struct lis3lv02d *lis3) +static int lis3lv02d_get_odr_index(struct lis3lv02d *lis3) { u8 ctrl; int shift; @@ -216,15 +216,23 @@ static int lis3lv02d_get_odr(struct lis3lv02d *lis3) lis3->read(lis3, CTRL_REG1, &ctrl); ctrl &= lis3->odr_mask; shift = ffs(lis3->odr_mask) - 1; - return lis3->odrs[(ctrl >> shift)]; + return (ctrl >> shift); } static int lis3lv02d_get_pwron_wait(struct lis3lv02d *lis3) { - int div = lis3lv02d_get_odr(lis3); + int odr_idx = lis3lv02d_get_odr_index(lis3); + int div = lis3->odrs[odr_idx]; - if (WARN_ONCE(div == 0, "device returned spurious data")) + if (div == 0) { + if (odr_idx == 0) { + /* Power-down mode, not sampling no need to sleep */ + return 0; + } + + dev_err(&lis3->pdev->dev, "Error unknown odrs-index: %d\n", odr_idx); return -ENXIO; + } /* LIS3 power on delay is quite long */ msleep(lis3->pwron_delay / div); @@ -816,9 +824,12 @@ static ssize_t lis3lv02d_rate_show(struct device *dev, struct device_attribute *attr, char *buf) { struct lis3lv02d *lis3 = dev_get_drvdata(dev); + int odr_idx; lis3lv02d_sysfs_poweron(lis3); - return sprintf(buf, "%d\n", lis3lv02d_get_odr(lis3)); + + odr_idx = lis3lv02d_get_odr_index(lis3); + return sprintf(buf, "%d\n", lis3->odrs[odr_idx]); } static ssize_t lis3lv02d_rate_set(struct device *dev, -- 2.30.1