From patchwork Tue Apr 12 06:30:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560727 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 156ABC433FE for ; Tue, 12 Apr 2022 06:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232882AbiDLG4U (ORCPT ); Tue, 12 Apr 2022 02:56:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350997AbiDLGwL (ORCPT ); Tue, 12 Apr 2022 02:52:11 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28F7829CAB; Mon, 11 Apr 2022 23:39:54 -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 ams.source.kernel.org (Postfix) with ESMTPS id 5DB7CB81B29; Tue, 12 Apr 2022 06:39:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A452DC385A1; Tue, 12 Apr 2022 06:39:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649745591; bh=s2sYS9As3u33Hzc2VpGCX1Osmu2wEWMTja/nF7fo7rk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JGVswMW6/ZtrHX/RWUWEyvAeNDtZ5pwQqVR7iYi0VIk0r4URK+mGKQytidmTBERFJ dhQ4dOjf9140i2qTO57FE91Oa8S0/gU6CTiLtGUUTKemYBO0vHcUXONYpjByTaIt9q /irxbTlRoBfwvf+Y7Ds6N7SdHNqzzD771F3+gjdo= 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 5.10 148/171] gpio: Restrict usage of GPIO chip irq members before initialization Date: Tue, 12 Apr 2022 08:30:39 +0200 Message-Id: <20220412062932.174571003@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062927.870347203@linuxfoundation.org> References: <20220412062927.870347203@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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 @@ -1411,6 +1411,16 @@ 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; @@ -1604,6 +1614,15 @@ 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