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 713B7C46467 for ; Tue, 12 Apr 2022 07:19:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350263AbiDLHVX (ORCPT ); Tue, 12 Apr 2022 03:21:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351835AbiDLHNA (ORCPT ); Tue, 12 Apr 2022 03:13:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EBDC17E15; Mon, 11 Apr 2022 23:53:24 -0700 (PDT) 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 A96D461451; Tue, 12 Apr 2022 06:53:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B74F2C385A6; Tue, 12 Apr 2022 06:53:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649746403; bh=fVdkxmCtnyf65DVQLtRAYKbRtUaCnvLBuvET/NqA9Bw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vO3W9Hvgt3oZqcE9eR2mgoG+aAq7+ak3g/rkfPlMjnYEDt1k4nw+U3YIBwBIlFTNH SV3bDnJAX0pwncVPvNTlPQFRcvKHXd4n94SdfgzlT6l0qs2SiVZLJUt1MkceRd+NFO nMus/InulibMHOyNHKAJBaFzZ74EKxvgwzHSce5U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shreeya Patel , Andy Shevchenko , Linus Walleij , Bartosz Golaszewski Subject: [PATCH 5.15 230/277] gpio: Restrict usage of GPIO chip irq members before initialization Date: Tue, 12 Apr 2022 08:30:33 +0200 Message-Id: <20220412062948.700437683@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062942.022903016@linuxfoundation.org> References: <20220412062942.022903016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Shreeya Patel commit 5467801f1fcbdc46bc7298a84dbf3ca1ff2a7320 upstream. GPIO chip irq members are exposed before they could be completely initialized and this leads to race conditions. One such issue was observed for the gc->irq.domain variable which was accessed through the I2C interface in gpiochip_to_irq() before it could be initialized by gpiochip_add_irqchip(). This resulted in Kernel NULL pointer dereference. Following are the logs for reference :- kernel: Call Trace: kernel: gpiod_to_irq+0x53/0x70 kernel: acpi_dev_gpio_irq_get_by+0x113/0x1f0 kernel: i2c_acpi_get_irq+0xc0/0xd0 kernel: i2c_device_probe+0x28a/0x2a0 kernel: really_probe+0xf2/0x460 kernel: RIP: 0010:gpiochip_to_irq+0x47/0xc0 To avoid such scenarios, restrict usage of GPIO chip irq members before they are completely initialized. Signed-off-by: Shreeya Patel Cc: stable@vger.kernel.org Reviewed-by: Andy Shevchenko Reviewed-by: Linus Walleij Signed-off-by: Bartosz Golaszewski Signed-off-by: Greg Kroah-Hartman --- drivers/gpio/gpiolib.c | 19 +++++++++++++++++++ include/linux/gpio/driver.h | 9 +++++++++ 2 files changed, 28 insertions(+) --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1368,6 +1368,16 @@ static int gpiochip_to_irq(struct gpio_c { struct irq_domain *domain = gc->irq.domain; +#ifdef CONFIG_GPIOLIB_IRQCHIP + /* + * 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. + */ + if (!gc->irq.initialized) + return -EPROBE_DEFER; +#endif + if (!gpiochip_irqchip_irq_valid(gc, offset)) return -ENXIO; @@ -1552,6 +1562,15 @@ static int gpiochip_add_irqchip(struct g acpi_gpiochip_request_interrupts(gc); + /* + * Using barrier() here to prevent compiler from reordering + * gc->irq.initialized before initialization of above + * GPIO chip irq members. + */ + barrier(); + + gc->irq.initialized = true; + return 0; } --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -225,6 +225,15 @@ struct gpio_irq_chip { unsigned int ngpios); /** + * @initialized: + * + * Flag to track GPIO chip irq member's initialization. + * This flag will make sure GPIO chip irq members are not used + * before they are initialized. + */ + bool initialized; + + /** * @valid_mask: * * If not %NULL, holds bitmask of GPIOs which are valid to be included