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gpiolib: fix memory leak in gpiochip_setup_dev() 

[ Upstream commit ec851b2308 ]

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: 159f3cd92f ("gpiolib: Defer gpio device setup until after gpiolib initialization")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zeng Heng 2022-11-25 22:07:57 +01:00 committed by Greg Kroah-Hartman
parent 16eb37b565
commit 3713637163
1 changed files with 26 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
drivers/gpio/gpiolib.c
View File

@ -526,12 +526,13 @@ 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");
@ -597,10 +598,10 @@ 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 (gc->fwnode)
fwnode = gc->fwnode;
@ -647,17 +648,12 @@ 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)
/*
@ -668,7 +664,7 @@ 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;
}
@ -676,13 +672,19 @@ 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;
@ -701,11 +703,13 @@ 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;
}
/*
@ -816,6 +820,11 @@ err_remove_of_chip:
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);
@ -829,13 +838,14 @@ err_free_dev_name:
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);