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 CDD78C4167E for ; Tue, 1 Mar 2022 20:24:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238158AbiCAUY6 (ORCPT ); Tue, 1 Mar 2022 15:24:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239240AbiCAUYh (ORCPT ); Tue, 1 Mar 2022 15:24:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15850237EC; Tue, 1 Mar 2022 12:22:32 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9D24F60AF5; Tue, 1 Mar 2022 20:22:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D205AC340EE; Tue, 1 Mar 2022 20:22:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646166151; bh=zntzQNFhfQ29E5DzxsfOSwyi2VweMUR+0XM7WCb2ZZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bzna50b2LJcGzdHxiuwzl0ZXZTqhmVvMTZi5GzCso0/Mnj6ZclAbQxudih3Eu2d32 2WlcTL5s05t0LPc9o5ZL65Pk0fs11c5RvIkXVpilZ1qL3NLA8koZfI6qegGx+uhXyM kGn7leomirhXU0PK6sTOMmtqG9L15zRk1G6zJwk23KVS7U1lHncVc6gQkKcWeOe1vF HWlnmLI8OnYxqhpecZKq+H1dfIk57b++3fGBwXEQxIxYZnRSaRiSZTgmEfFbqUcScH DRwQ9t1savPpmwDkwcRHUNengySPUb87FVLVdHuPNyW9ho8nAevnfbo95Q2081L202 tHiklY57B4AxA== 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 4.9 3/6] gpio: Return EPROBE_DEFER if gc->to_irq is NULL Date: Tue, 1 Mar 2022 15:22:07 -0500 Message-Id: <20220301202212.19419-3-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220301202212.19419-1-sashal@kernel.org> References: <20220301202212.19419-1-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 73d02f6089d56..a01bf4145beda 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2726,6 +2726,16 @@ 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