From patchwork Fri Nov 18 19:45:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Shevchenko X-Patchwork-Id: 626459 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 5FBC8C433FE for ; Fri, 18 Nov 2022 19:44:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235272AbiKRToy (ORCPT ); Fri, 18 Nov 2022 14:44:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235279AbiKRTou (ORCPT ); Fri, 18 Nov 2022 14:44:50 -0500 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E0E78CFE1; Fri, 18 Nov 2022 11:44:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668800689; x=1700336689; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=QaFNElBI+fgLVtzxPva2EljaafBhBXrc+lLrYy1kfP4=; b=BKlqC9YPWdEL5agqWl4CxWsID1MNaPWqDfviiHEeZX2CngNgRgGl8l8k CCBGeeLkAa7TGfOQBMv2cJr9iH3rRaXdSVlRuD1GdC3aJnegq4Es1omsL hzAlIkEcV0dUAekkyAuKj1lTdZCIo9X1rd7Gzu0WNuaMGpS19E3tLOg8B 9LqGdFUmefaQQEilnhrjjEx336ClaPlnAWiOa4rC+NGqZvucDvOkHryKz gd1HiP/UghvFC/rwGyycorCZ1Q2C6lM+MwhgS4ROS/avLnC75GVxPHrk0 YYiHzte/VfL5lmHlH2xwBc1wqRdwv/F2OPwSx4jUIlMloFwNrAKbLIReO g==; X-IronPort-AV: E=McAfee;i="6500,9779,10535"; a="310849264" X-IronPort-AV: E=Sophos;i="5.96,175,1665471600"; d="scan'208";a="310849264" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2022 11:44:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10535"; a="709143035" X-IronPort-AV: E=Sophos;i="5.96,175,1665471600"; d="scan'208";a="709143035" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga004.fm.intel.com with ESMTP; 18 Nov 2022 11:44:46 -0800 Received: by black.fi.intel.com (Postfix, from userid 1003) id 230AE10E; Fri, 18 Nov 2022 21:45:11 +0200 (EET) From: Andy Shevchenko To: Bartosz Golaszewski , Andy Shevchenko , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Linus Walleij , Zeng Heng Subject: [rft, PATCH v5 1/1] gpiolib: fix memory leak in gpiochip_setup_dev() Date: Fri, 18 Nov 2022 21:45:08 +0200 Message-Id: <20221118194508.50686-1-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Zeng Heng Here is a backtrace report about memory leak detected in gpiochip_setup_dev(): unreferenced object 0xffff88810b406400 (size 512): comm "python3", pid 1682, jiffies 4295346908 (age 24.090s) backtrace: kmalloc_trace device_add device_private_init at drivers/base/core.c:3361 (inlined by) device_add at drivers/base/core.c:3411 cdev_device_add gpiolib_cdev_register gpiochip_setup_dev gpiochip_add_data_with_key gcdev_register() & gcdev_unregister() would call device_add() & device_del() (no matter CONFIG_GPIO_CDEV is enabled or not) to register/unregister device. However, if device_add() succeeds, some resource (like struct device_private allocated by device_private_init()) is not released by device_del(). Therefore, after device_add() succeeds by gcdev_register(), it needs to call put_device() to release resource in the error handle path. Here we move forward the register of release function, and let it release every piece of resource by put_device() instead of kfree(). While at it, fix another subtle issue, i.e. when gc->ngpio is equal to 0, we still call kcalloc() and, in case of further error, kfree() on the ZERO_PTR pointer, which is not NULL. It's not a bug per se, but rather waste of the resources and potentially wrong expectation about contents of the gdev->descs variable. Fixes: 159f3cd92f17 ("gpiolib: Defer gpio device setup until after gpiolib initialization") Signed-off-by: Zeng Heng Co-developed-by: Andy Shevchenko Signed-off-by: Andy Shevchenko --- changes in v5 (done by Andy): - refactored to avoid double checks on the same conditionals - moved kcalloc() after validating its parameter - compiled tested only by me (Andy) changes in v4: - add gpiochip_print_register_fail() changes in v3: - use put_device() instead of kfree() explicitly changes in v2: - correct fixes tag drivers/gpio/gpiolib.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index caa747fdcb72..119c9c3a2a50 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -580,12 +580,13 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) if (ret) return ret; + /* From this point, the .release() function cleans up gpio_device */ + gdev->dev.release = gpiodevice_release; + ret = gpiochip_sysfs_register(gdev); if (ret) goto err_remove_device; - /* From this point, the .release() function cleans up gpio_device */ - gdev->dev.release = gpiodevice_release; dev_dbg(&gdev->dev, "registered GPIOs %d to %d on %s\n", gdev->base, gdev->base + gdev->ngpio - 1, gdev->chip->label ? : "generic"); @@ -651,10 +652,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, struct fwnode_handle *fwnode = NULL; struct gpio_device *gdev; unsigned long flags; - int base = gc->base; unsigned int i; + u32 ngpios = 0; + int base = 0; int ret = 0; - u32 ngpios; /* If the calling driver did not initialize firmware node, do it here */ if (gc->fwnode) @@ -696,17 +697,12 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, else gdev->owner = THIS_MODULE; - gdev->descs = kcalloc(gc->ngpio, sizeof(gdev->descs[0]), GFP_KERNEL); - if (!gdev->descs) { - ret = -ENOMEM; - goto err_free_dev_name; - } - /* * Try the device properties if the driver didn't supply the number * of GPIO lines. */ - if (gc->ngpio == 0) { + ngpios = gc->ngpio; + if (ngpios == 0) { ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios); if (ret == -ENODATA) /* @@ -717,7 +713,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, */ ngpios = 0; else if (ret) - goto err_free_descs; + goto err_free_dev_name; gc->ngpio = ngpios; } @@ -725,13 +721,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (gc->ngpio == 0) { chip_err(gc, "tried to insert a GPIO chip with zero lines\n"); ret = -EINVAL; - goto err_free_descs; + goto err_free_dev_name; } if (gc->ngpio > FASTPATH_NGPIO) chip_warn(gc, "line cnt %u is greater than fast path cnt %u\n", gc->ngpio, FASTPATH_NGPIO); + gdev->descs = kcalloc(gc->ngpio, sizeof(*gdev->descs), GFP_KERNEL); + if (!gdev->descs) { + ret = -ENOMEM; + goto err_free_dev_name; + } + gdev->label = kstrdup_const(gc->label ?: "unknown", GFP_KERNEL); if (!gdev->label) { ret = -ENOMEM; @@ -750,11 +752,13 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, * it may be a pipe dream. It will not happen before we get rid * of the sysfs interface anyways. */ + base = gc->base; if (base < 0) { base = gpiochip_find_base(gc->ngpio); if (base < 0) { - ret = base; spin_unlock_irqrestore(&gpio_lock, flags); + ret = base; + base = 0; goto err_free_label; } /* @@ -868,6 +872,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, err_free_gpiochip_mask: gpiochip_remove_pin_ranges(gc); gpiochip_free_valid_mask(gc); + if (gdev->dev.release) { + /* release() has been registered by gpiochip_setup_dev() */ + put_device(&gdev->dev); + goto err_print_message; + } err_remove_from_list: spin_lock_irqsave(&gpio_lock, flags); list_del(&gdev->list); @@ -881,13 +890,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, err_free_ida: ida_free(&gpio_ida, gdev->id); err_free_gdev: + kfree(gdev); +err_print_message: /* failures here can mean systems won't boot... */ if (ret != -EPROBE_DEFER) { pr_err("%s: GPIOs %d..%d (%s) failed to register, %d\n", __func__, - gdev->base, gdev->base + gdev->ngpio - 1, + base, base + (int)ngpios - 1, gc->label ? : "generic", ret); } - kfree(gdev); return ret; } EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key);