On 02/26/2020 04:09 PM, Johan Hovold wrote:
On Wed, Feb 26, 2020 at 02:15:23PM +0800, Tiezhu Yang wrote:
Make sure to free all the allocated memory before exiting from the function
usb_get_configuration() when an error is encountered.
There's no leak in this function as far as I can tell. Any allocated
memory is released in usb_destroy_configuration() when the last
reference to the struct usb_device is dropped.
Yes, you are right, the allocated memory in usb_get_configuration()
will be released in usb_destroy_configuration().
By the way, is it better to release the allocated memory as early as
possible
in usb_get_configuration()? Just like this:
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index bb63ee0..dd4ebeb 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -885,12 +885,17 @@ int usb_get_configuration(struct usb_device *dev)
length = ncfg * sizeof(char *);
dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
- if (!dev->rawdescriptors)
+ if (!dev->rawdescriptors) {
+ kfree(dev->config);
return -ENOMEM;
+ }
desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
- if (!desc)
+ if (!desc) {
+ kfree(dev->config);
+ kfree(dev->rawdescriptors);
return -ENOMEM;
+ }
for (cfgno = 0; cfgno < ncfg; cfgno++) {
/* We grab just the first descriptor so we know how long
Thanks,
Tiezhu Yang
Additionally, just initialize the variable "bigbuffer" with NULL to avoid
the following build warning:
CC drivers/usb/core/config.o
drivers/usb/core/config.c: In function ‘usb_get_configuration’:
drivers/usb/core/config.c:956:2: warning: ‘bigbuffer’ may be used uninitialized in this function [-Wmaybe-uninitialized]
kfree(bigbuffer);
^
No need to mention warnings that you introduce yourself while creating
your patch. It can give the false impression that your addressing an
existing issue.
Johan
