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 F3CFEC004C0 for ; Mon, 23 Oct 2023 11:00:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229613AbjJWLAx (ORCPT ); Mon, 23 Oct 2023 07:00:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229753AbjJWLAv (ORCPT ); Mon, 23 Oct 2023 07:00:51 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D22C910CC for ; Mon, 23 Oct 2023 04:00:48 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 086C7C433CA; Mon, 23 Oct 2023 11:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698058848; bh=gwqWIMTDBhwDW0+eokoTnGxfx7m9H8VaHAP0sy95oFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LpHqSqn700mM4Js2zxUyJCeDhReJ11u1igkt8HRsfyGYmR4rTCEzvOIy7IGoNUBRA e4fTzyHSCRO8aBkK/7MssbR+Hx+YcZYwtfZXU1WmFltC8gTWZxkWZNy6Ph5hp9ILuP Ftcpx+1dTgFaaz4nFtiS0MCJFmclygbq6imF/BXM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Andy Shevchenko , Bartosz Golaszewski , Sasha Levin Subject: [PATCH 4.14 46/66] gpio: timberdale: Fix potential deadlock on &tgpio->lock Date: Mon, 23 Oct 2023 12:56:36 +0200 Message-ID: <20231023104812.550515578@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104810.781270702@linuxfoundation.org> References: <20231023104810.781270702@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye [ Upstream commit 9e8bc2dda5a7a8e2babc9975f4b11c9a6196e490 ] As timbgpio_irq_enable()/timbgpio_irq_disable() callback could be executed under irq context, it could introduce double locks on &tgpio->lock if it preempts other execution units requiring the same locks. timbgpio_gpio_set() --> timbgpio_update_bit() --> spin_lock(&tgpio->lock) --> timbgpio_irq_disable() --> spin_lock_irqsave(&tgpio->lock) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. To prevent the potential deadlock, the patch uses spin_lock_irqsave() on &tgpio->lock inside timbgpio_gpio_set() to prevent the possible deadlock scenario. Signed-off-by: Chengfeng Ye Reviewed-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski Signed-off-by: Sasha Levin --- drivers/gpio/gpio-timberdale.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpio-timberdale.c b/drivers/gpio/gpio-timberdale.c index 181f86ce00cd4..639c8daaeb310 100644 --- a/drivers/gpio/gpio-timberdale.c +++ b/drivers/gpio/gpio-timberdale.c @@ -55,9 +55,10 @@ static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index, unsigned offset, bool enabled) { struct timbgpio *tgpio = gpiochip_get_data(gpio); + unsigned long flags; u32 reg; - spin_lock(&tgpio->lock); + spin_lock_irqsave(&tgpio->lock, flags); reg = ioread32(tgpio->membase + offset); if (enabled) @@ -66,7 +67,7 @@ static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index, reg &= ~(1 << index); iowrite32(reg, tgpio->membase + offset); - spin_unlock(&tgpio->lock); + spin_unlock_irqrestore(&tgpio->lock, flags); return 0; } -- 2.40.1