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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 autolearn=ham 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 A7F41C4361B for ; Sat, 5 Dec 2020 18:30:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 717B7229C4 for ; Sat, 5 Dec 2020 18:30:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729019AbgLESao (ORCPT ); Sat, 5 Dec 2020 13:30:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:56222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728800AbgLES3y (ORCPT ); Sat, 5 Dec 2020 13:29:54 -0500 Received: from archlinux (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A5F63229C4; Sat, 5 Dec 2020 18:29:12 +0000 (UTC) Date: Sat, 5 Dec 2020 18:29:07 +0000 From: Jonathan Cameron To: Lorenzo Bianconi Cc: lorenzo.bianconi@redhat.com, linux-iio@vger.kernel.org, linus.walleij@linaro.org, denis.ciocca@st.com Subject: Re: [PATCH v2] iio: common: st_sensors: fix possible infinite loop in st_sensors_irq_thread Message-ID: <20201205182907.5d2c948e@archlinux> In-Reply-To: <58d40383f6e1faa14850f3a9b694b8e4cb4fbbec.1607162799.git.lorenzo@kernel.org> References: <58d40383f6e1faa14850f3a9b694b8e4cb4fbbec.1607162799.git.lorenzo@kernel.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sat, 5 Dec 2020 11:10:41 +0100 Lorenzo Bianconi wrote: > Return a boolean value in st_sensors_new_samples_available routine in > order to avoid an infinite loop in st_sensors_irq_thread if > stat_drdy.addr is not defined or stat_drdy read fails > > Fixes: 90efe05562921 ("iio: st_sensors: harden interrupt handling") > Reported-by: Jonathan Cameron > Reviewed-by: Linus Walleij > Signed-off-by: Lorenzo Bianconi Oops. I should not noticed this and replied here. See reply to previous version. I think this will create an infinite loop in the obscure case of no status register + an edge interrupt. My gut feeling is we can't support that combination so should fail at probe time if it is specified. It's broken hardware / dt. Jonathan > --- > Changes since v1: > - return true if the sensor does not have stat_drdy register > --- > .../common/st_sensors/st_sensors_trigger.c | 20 ++++++++----------- > 1 file changed, 8 insertions(+), 12 deletions(-) > > diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c > index 0507283bd4c1..d3f047e9d778 100644 > --- a/drivers/iio/common/st_sensors/st_sensors_trigger.c > +++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c > @@ -23,35 +23,31 @@ > * @sdata: Sensor data. > * > * returns: > - * 0 - no new samples available > - * 1 - new samples available > - * negative - error or unknown > + * false - no new samples available or read error > + * true - new samples available > */ > -static int st_sensors_new_samples_available(struct iio_dev *indio_dev, > - struct st_sensor_data *sdata) > +static bool st_sensors_new_samples_available(struct iio_dev *indio_dev, > + struct st_sensor_data *sdata) > { > int ret, status; > > /* How would I know if I can't check it? */ > if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) > - return -EINVAL; > + return true; > > /* No scan mask, no interrupt */ > if (!indio_dev->active_scan_mask) > - return 0; > + return false; > > ret = regmap_read(sdata->regmap, > sdata->sensor_settings->drdy_irq.stat_drdy.addr, > &status); > if (ret < 0) { > dev_err(sdata->dev, "error checking samples available\n"); > - return ret; > + return false; > } > > - if (status & sdata->sensor_settings->drdy_irq.stat_drdy.mask) > - return 1; > - > - return 0; > + return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask); > } > > /**