From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4980963B7 for ; Thu, 2 Feb 2023 14:11:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D28FC433EF; Thu, 2 Feb 2023 14:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675347101; bh=975b4kPA+NLq0YmeXLwxMZvqYcj3aaM9QWDIE/DupWk=; h=From:To:Cc:Subject:Date:From; b=SXvYC5vW2/L1O1Nmo3J3G2R2uHvLHPxvr+dq4MsIg5JINzOumTQvcanJNMoRNI6kc au35FOqbILogiDGy/cksnHKxUE41nkziisq/3G3XgOEexLL9+9hsIB6/PZOf6oNyQT f/ygnynDxAqGmFnATDmvaxW/V98Q7bHemdVr3LLc= From: Greg Kroah-Hartman To: linux-staging@lists.linux.dev Cc: Greg Kroah-Hartman , Paulo Miguel Almeida , Dan Carpenter , Sidong Yang , Liu Shixin , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , linux-kernel@vger.kernel.org Subject: [PATCH] staging: pi433: fix memory leak with using debugfs_lookup() Date: Thu, 2 Feb 2023 15:11:38 +0100 Message-Id: <20230202141138.2291946-1-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Developer-Signature: v=1; a=openpgp-sha256; l=2772; i=gregkh@linuxfoundation.org; h=from:subject; bh=975b4kPA+NLq0YmeXLwxMZvqYcj3aaM9QWDIE/DupWk=; b=owGbwMvMwCRo6H6F97bub03G02pJDMm3j8zytqh9Wbmqb4ewgPrVYxwNlXwHpz9ft/HQw8lLV/aL L1X42BHLwiDIxCArpsjyZRvP0f0VhxS9DG1Pw8xhZQIZwsDFKQATMQ9gWHBL+vyp15oGrUJyT9rm5l 1gfMhg/Jphnl3WP23VaZxSEhErxFp5J53ucV9xHwA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once. This requires saving off the root directory dentry to make creation of individual device subdirectories easier. Cc: Paulo Miguel Almeida Cc: Dan Carpenter Cc: Sidong Yang Cc: Liu Shixin Cc: "Uwe Kleine-König" Cc: linux-staging@lists.linux.dev Cc: linux-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/staging/pi433/pi433_if.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c index d4e06a3929f3..b59f6a4cb611 100644 --- a/drivers/staging/pi433/pi433_if.c +++ b/drivers/staging/pi433/pi433_if.c @@ -55,6 +55,7 @@ static dev_t pi433_dev; static DEFINE_IDR(pi433_idr); static DEFINE_MUTEX(minor_lock); /* Protect idr accesses */ +static struct dentry *root_dir; /* debugfs root directory for the driver */ static struct class *pi433_class; /* mainly for udev to create /dev/pi433 */ @@ -1306,8 +1307,7 @@ static int pi433_probe(struct spi_device *spi) /* spi setup */ spi_set_drvdata(spi, device); - entry = debugfs_create_dir(dev_name(device->dev), - debugfs_lookup(KBUILD_MODNAME, NULL)); + entry = debugfs_create_dir(dev_name(device->dev), root_dir); debugfs_create_file("regs", 0400, entry, device, &pi433_debugfs_regs_fops); return 0; @@ -1333,9 +1333,8 @@ static int pi433_probe(struct spi_device *spi) static void pi433_remove(struct spi_device *spi) { struct pi433_device *device = spi_get_drvdata(spi); - struct dentry *mod_entry = debugfs_lookup(KBUILD_MODNAME, NULL); - debugfs_remove(debugfs_lookup(dev_name(device->dev), mod_entry)); + debugfs_lookup_and_remove(dev_name(device->dev), root_dir); /* free GPIOs */ free_gpio(device); @@ -1408,7 +1407,7 @@ static int __init pi433_init(void) return PTR_ERR(pi433_class); } - debugfs_create_dir(KBUILD_MODNAME, NULL); + root_dir = debugfs_create_dir(KBUILD_MODNAME, NULL); status = spi_register_driver(&pi433_spi_driver); if (status < 0) { @@ -1427,7 +1426,7 @@ static void __exit pi433_exit(void) spi_unregister_driver(&pi433_spi_driver); class_destroy(pi433_class); unregister_chrdev(MAJOR(pi433_dev), pi433_spi_driver.driver.name); - debugfs_remove_recursive(debugfs_lookup(KBUILD_MODNAME, NULL)); + debugfs_remove(root_dir); } module_exit(pi433_exit); -- 2.39.1