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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 1B4E9C433FC for ; Tue, 14 Jul 2020 19:05:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC4EC208C3 for ; Tue, 14 Jul 2020 19:05:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594753508; bh=WnWXystKD1gPfAT1UfcvNWEFGL4xdS81LhQZ9qwrS4E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jit8HR54LyCqHu72yUv3Ix2fKVtjFU0Ok4Ed1Hvfz5LHIrdp2P62jYKRKngJ757jq xXERa+vC5dHxKuP+vlmJNW/eDh2pWS6g/r8BcK3pcy/xN1kf8ROkkdNy4BV6iftuCh HKNTIi4JHrUA2pd4CKlBAdzz0Db4SgTI2Id06HEg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730301AbgGNTFH (ORCPT ); Tue, 14 Jul 2020 15:05:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:52798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730433AbgGNSzL (ORCPT ); Tue, 14 Jul 2020 14:55:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 7807B22BEF; Tue, 14 Jul 2020 18:55:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752911; bh=WnWXystKD1gPfAT1UfcvNWEFGL4xdS81LhQZ9qwrS4E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jplqxF7/0sHcaobw28HmgCeN71O2qSC31B/HCHxWF7kS2Xf+xJpGCnXg3ZLeMMQ+T C853mqWFKJIkRXzIBMTc0T/DFGOHwUsuhumKbr4/gw9JcBd5OO06HSSKcspKl/WVxu 26schXjtwAdCWnGDUfcyEIj7u3Je+AFB74DYNvBs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marek Vasut , Roland Stigge , Andy Shevchenko , Bartosz Golaszewski , Sasha Levin Subject: [PATCH 5.7 047/166] gpio: pca953x: Synchronize interrupt handler properly Date: Tue, 14 Jul 2020 20:43:32 +0200 Message-Id: <20200714184118.135701674@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184115.844176932@linuxfoundation.org> References: <20200714184115.844176932@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andy Shevchenko [ Upstream commit 064c73afe7385de99e5b2785b88c83dc5d84403b ] Since the commit aa58a21ae378 ("gpio: pca953x: disable regmap locking") the locking of regmap is disabled and that immediately introduces a synchronization issue. It's easy to see when we try to monitor more than one interrupt from the same chip. It seems that the problem exists from the day one and even commit 6e20fb18054c ("drivers/gpio/pca953x.c: add a mutex to fix race condition") missed this. Below are the traces and shell reproducers before and after proposed change. Note duplicates in the IRQ events. /proc/interrupts also shows a deviation, i.e. sum of children interrupts higher than parent's one. When locking is disabled for regmap and no protection in IRQ handler ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ... gpioset-194 regmap_hw_write_start: i2c-INT3491:02 reg=2 count=1 irq/31-i2c-INT3-139 regmap_hw_read_start: i2c-INT3491:02 reg=4c count=2 gpioset-194 regmap_hw_write_done: i2c-INT3491:02 reg=2 count=1 gpioset-194 regmap_reg_read_cache: i2c-INT3491:02 reg=6 val=f5 gpioset-194 regmap_reg_write: i2c-INT3491:02 reg=6 val=f5 gpioset-194 regmap_hw_write_start: i2c-INT3491:02 reg=6 count=1 irq/31-i2c-INT3-139 regmap_hw_read_done: i2c-INT3491:02 reg=4c count=2 ... % gpiomon gpiochip3 0 & % gpioset gpiochip3 1=0 % gpioset gpiochip3 1=1 event: RISING EDGE offset: 0 timestamp: [ 302.782583765] % gpiomon gpiochip3 2 & % gpioset gpiochip3 1=0 event: RISING EDGE offset: 2 timestamp: [ 312.033148829] event: FALLING EDGE offset: 0 timestamp: [ 312.022757525] % gpioset gpiochip3 1=1 event: RISING EDGE offset: 2 timestamp: [ 316.201148473] event: RISING EDGE offset: 0 timestamp: [ 316.191759599] When locking is disabled for regmap and protection in IRQ handler ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ... gpioset-202 regmap_hw_write_start: i2c-INT3491:02 reg=2 count=1 gpioset-202 regmap_hw_write_done: i2c-INT3491:02 reg=2 count=1 gpioset-202 regmap_reg_read_cache: i2c-INT3491:02 reg=6 val=fd gpioset-202 regmap_reg_write: i2c-INT3491:02 reg=6 val=fd gpioset-202 regmap_hw_write_start: i2c-INT3491:02 reg=6 count=1 gpioset-202 regmap_hw_write_done: i2c-INT3491:02 reg=6 count=1 irq/31-i2c-INT3-139 regmap_hw_read_start: i2c-INT3491:02 reg=4c count=2 irq/31-i2c-INT3-139 regmap_hw_read_done: i2c-INT3491:02 reg=4c count=2 ... % gpiomon gpiochip3 0 & % gpioset gpiochip3 1=0 event: FALLING EDGE offset: 0 timestamp: [ 531.330078107] % gpioset gpiochip3 1=1 event: RISING EDGE offset: 0 timestamp: [ 532.912239128] % gpiomon gpiochip3 2 & % gpioset gpiochip3 1=0 event: FALLING EDGE offset: 0 timestamp: [ 539.633669484] % gpioset gpiochip3 1=1 event: RISING EDGE offset: 0 timestamp: [ 542.256978461] Fixes: 6e20fb18054c ("drivers/gpio/pca953x.c: add a mutex to fix race condition") Depends-on: 35d13d94893f ("gpio: pca953x: convert to use bitmap API") Depends-on: 49427232764d ("gpio: pca953x: Perform basic regmap conversion") Cc: Marek Vasut Cc: Roland Stigge Signed-off-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski Signed-off-by: Sasha Levin --- drivers/gpio/gpio-pca953x.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 01011a780688a..d8ba6c5195be7 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -724,14 +724,16 @@ static irqreturn_t pca953x_irq_handler(int irq, void *devid) struct gpio_chip *gc = &chip->gpio_chip; DECLARE_BITMAP(pending, MAX_LINE); int level; + bool ret; - if (!pca953x_irq_pending(chip, pending)) - return IRQ_NONE; + mutex_lock(&chip->i2c_lock); + ret = pca953x_irq_pending(chip, pending); + mutex_unlock(&chip->i2c_lock); for_each_set_bit(level, pending, gc->ngpio) handle_nested_irq(irq_find_mapping(gc->irq.domain, level)); - return IRQ_HANDLED; + return IRQ_RETVAL(ret); } static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base) -- 2.25.1