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 2792DC433F5 for ; Tue, 1 Mar 2022 20:16:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237805AbiCAUQw (ORCPT ); Tue, 1 Mar 2022 15:16:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237831AbiCAUQl (ORCPT ); Tue, 1 Mar 2022 15:16:41 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A97657F6D2; Tue, 1 Mar 2022 12:15:38 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 532E7B81D18; Tue, 1 Mar 2022 20:15:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C759EC340FC; Tue, 1 Mar 2022 20:15:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646165736; bh=szJFOZCUhlXeA7ihv1MS281AU6Nwo6IQMXRbRGEeYK4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZOpzqdHND0PgsZveoeK2XENd6kvZQ1S88WwBoS6uBEeWQ8NoG55kObarm6j1Ljjd7 54eLtBkriu6w1ThBiuKWA8S8M6sW2naiXzyESTbvc5Zx6lgXCceIK4KQyxNBeq57Fi hH5lKRuGlY6mrkQRz4SFrFbQnepT93VxZpNYkms/FFeSAQ7tXOtzuwxhpK4SO5iDu+ YBOI3uJqxrFOfU2FRxv66mAJPdbot/M66MgLvISiRGbYyTxOKBD/QGRspkWCHONIdg aM9O0UjH4KRBYYDS9CjAwKGtAIe5ssL6ceCabTMYWfIc6Hy+jg2oimR+179LpTDl4m 7v3yW7evXWDwQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Shreeya Patel , Linus Walleij , Andy Shevchenko , kernel test robot , Bartosz Golaszewski , Sasha Levin , linux-gpio@vger.kernel.org Subject: [PATCH AUTOSEL 5.16 19/28] gpio: Return EPROBE_DEFER if gc->to_irq is NULL Date: Tue, 1 Mar 2022 15:13:24 -0500 Message-Id: <20220301201344.18191-19-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220301201344.18191-1-sashal@kernel.org> References: <20220301201344.18191-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Shreeya Patel [ Upstream commit ae42f9288846353982e2eab181fb41e7fd8bf60f ] We are racing the registering of .to_irq when probing the i2c driver. This results in random failure of touchscreen devices. Following explains the race condition better. [gpio driver] gpio driver registers gpio chip [gpio consumer] gpio is acquired [gpio consumer] gpiod_to_irq() fails with -ENXIO [gpio driver] gpio driver registers irqchip gpiod_to_irq works at this point, but -ENXIO is fatal We could see the following errors in dmesg logs when gc->to_irq is NULL [2.101857] i2c_hid i2c-FTS3528:00: HID over i2c has not been provided an Int IRQ [2.101953] i2c_hid: probe of i2c-FTS3528:00 failed with error -22 To avoid this situation, defer probing until to_irq is registered. Returning -EPROBE_DEFER would be the first step towards avoiding the failure of devices due to the race in registration of .to_irq. Final solution to this issue would be to avoid using gc irq members until they are fully initialized. This issue has been reported many times in past and people have been using workarounds like changing the pinctrl_amd to built-in instead of loading it as a module or by adding a softdep for pinctrl_amd into the config file. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209413 Reviewed-by: Linus Walleij Reviewed-by: Andy Shevchenko Reported-by: kernel test robot Signed-off-by: Shreeya Patel Signed-off-by: Bartosz Golaszewski Signed-off-by: Sasha Levin --- drivers/gpio/gpiolib.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index abfbf546d1599..7b3f7f4d1d063 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -3111,6 +3111,16 @@ int gpiod_to_irq(const struct gpio_desc *desc) return retirq; } +#ifdef CONFIG_GPIOLIB_IRQCHIP + if (gc->irq.chip) { + /* + * Avoid race condition with other code, which tries to lookup + * an IRQ before the irqchip has been properly registered, + * i.e. while gpiochip is still being brought up. + */ + return -EPROBE_DEFER; + } +#endif return -ENXIO; } EXPORT_SYMBOL_GPL(gpiod_to_irq); -- 2.34.1