linux-kernel - [PATCH] gpiolib: free device name on error path to fix kmemleak

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Date:   Fri, 29 Jan 2021 16:19:17 +0800
From:   quanyang.wang@...driver.com
To:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] gpiolib: free device name on error path to fix kmemleak

From: Quanyang Wang <quanyang.wang@...driver.com>

In gpiochip_add_data_with_key, we should check the return value of
dev_set_name to ensure that device name is allocated successfully
and then add a label on the error path to free device name to fix
kmemleak as below:

unreferenced object 0xc2d6fc40 (size 64):
  comm "kworker/0:1", pid 16, jiffies 4294937425 (age 65.120s)
  hex dump (first 32 bytes):
    67 70 69 6f 63 68 69 70 30 00 1a c0 54 63 1a c0  gpiochip0...Tc..
    0c ed 84 c0 48 ed 84 c0 3c ee 84 c0 10 00 00 00  ....H...<.......
  backtrace:
    [<962810f7>] kobject_set_name_vargs+0x2c/0xa0
    [<f50797e6>] dev_set_name+0x2c/0x5c
    [<94abbca9>] gpiochip_add_data_with_key+0xfc/0xce8
    [<5c4193e0>] omap_gpio_probe+0x33c/0x68c
    [<3402f137>] platform_probe+0x58/0xb8
    [<7421e210>] really_probe+0xec/0x3b4
    [<000f8ada>] driver_probe_device+0x58/0xb4
    [<67e0f7f7>] bus_for_each_drv+0x80/0xd0
    [<4de545dc>] __device_attach+0xe8/0x15c
    [<2e4431e7>] bus_probe_device+0x84/0x8c
    [<c18b1de9>] device_add+0x384/0x7c0
    [<5aff2995>] of_platform_device_create_pdata+0x8c/0xb8
    [<061c3483>] of_platform_bus_create+0x198/0x230
    [<5ee6d42a>] of_platform_populate+0x60/0xb8
    [<2647300f>] sysc_probe+0xd18/0x135c
    [<3402f137>] platform_probe+0x58/0xb8

Signed-off-by: Quanyang Wang <quanyang.wang@...driver.com>
---
 drivers/gpio/gpiolib.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 7e1ad4d40e0a..091e00f2e0a9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -603,7 +603,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 		ret = gdev->id;
 		goto err_free_gdev;
 	}
-	dev_set_name(&gdev->dev, GPIOCHIP_NAME "%d", gdev->id);
+
+	ret = dev_set_name(&gdev->dev, GPIOCHIP_NAME "%d", gdev->id);
+	if (ret)
+		goto err_free_ida;
+
 	device_initialize(&gdev->dev);
 	dev_set_drvdata(&gdev->dev, gdev);
 	if (gc->parent && gc->parent->driver)
@@ -617,7 +621,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	gdev->descs = kcalloc(gc->ngpio, sizeof(gdev->descs[0]), GFP_KERNEL);
 	if (!gdev->descs) {
 		ret = -ENOMEM;
-		goto err_free_ida;
+		goto err_free_dev_name;
 	}
 
 	if (gc->ngpio == 0) {
@@ -768,6 +772,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	kfree_const(gdev->label);
 err_free_descs:
 	kfree(gdev->descs);
+err_free_dev_name:
+	kfree(dev_name(&gdev->dev));
 err_free_ida:
 	ida_free(&gpio_ida, gdev->id);
 err_free_gdev:
-- 
2.25.1