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 35CFEC83F1B for ; Tue, 29 Aug 2023 13:35:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233230AbjH2Net (ORCPT ); Tue, 29 Aug 2023 09:34:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236221AbjH2Ndf (ORCPT ); Tue, 29 Aug 2023 09:33:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8964719F; Tue, 29 Aug 2023 06:33:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0908065763; Tue, 29 Aug 2023 13:32:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5C39C433C8; Tue, 29 Aug 2023 13:32:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1693315961; bh=BUv0dUR3yzGvu4wJm1+oQsHMjru5un0H9rT5BRsHxwE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SURM7Ql5Zqxtk8leYdDQFmnwzsmKG5B6JKl+/dEM4qHsJ7S5lJ5z7bkpjBdWDWyv8 kox/X8N07zmJEeXfl88eOIVjAbMhu5FVsCTtNc+LbNG5yu5Qn9ySeJ52ni9XG4EoFc 1VlJQJlSntWjlwckvX0WpgmmWpwHIMqE3rPil/S0vPyHp7R90IZe8nEdryod94iAa1 a3Ln8qca9cOi250KYyr+Kmwzi8BIhvPYzMAuq4l+YUz8WIIUVmIGsIQ6tWTn8W5OTV 7ffRv8qKwySlyphvcvMo9Fy7BySxOYyZEAh/sR2DnSRejoSCa9t+OYCbSMkh+IMjvF q+XtfaBl2WL5A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bartosz Golaszewski , Linus Walleij , Sasha Levin , brgl@bgdev.pl, linux-gpio@vger.kernel.org Subject: [PATCH AUTOSEL 6.4 16/17] gpiolib: fix reference leaks when removing GPIO chips still in use Date: Tue, 29 Aug 2023 09:32:03 -0400 Message-Id: <20230829133211.519957-16-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230829133211.519957-1-sashal@kernel.org> References: <20230829133211.519957-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.12 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bartosz Golaszewski [ Upstream commit 3386fb86ecdef0d39ee3306aea8ec290e61b934f ] After we remove a GPIO chip that still has some requested descriptors, gpiod_free_commit() will fail and we will never put the references to the GPIO device and the owning module in gpiod_free(). Rework this function to: - not warn on desc == NULL as this is a use-case on which most free functions silently return - put the references to desc->gdev and desc->gdev->owner unconditionally so that the release callback actually gets called when the remaining references are dropped by external GPIO users Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij Signed-off-by: Sasha Levin --- drivers/gpio/gpiolib.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 5be8ad61523eb..6e7701f80929f 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2175,12 +2175,18 @@ static bool gpiod_free_commit(struct gpio_desc *desc) void gpiod_free(struct gpio_desc *desc) { - if (desc && desc->gdev && gpiod_free_commit(desc)) { - module_put(desc->gdev->owner); - gpio_device_put(desc->gdev); - } else { + /* + * We must not use VALIDATE_DESC_VOID() as the underlying gdev->chip + * may already be NULL but we still want to put the references. + */ + if (!desc) + return; + + if (!gpiod_free_commit(desc)) WARN_ON(extra_checks); - } + + module_put(desc->gdev->owner); + gpio_device_put(desc->gdev); } /** -- 2.40.1