Bjørn Mork <bjorn@xxxxxxx> writes:
> Oliver Neukum <oneukum@xxxxxxx> writes:
>
>> From a1d8ec5966fb20dcc30f40ee3a253f3228d7e716 Mon Sep 17 00:00:00 2001
>> From: Oliver Neukum <oliver@xxxxxxxxxx>
>> Date: Fri, 27 Apr 2012 14:36:37 +0200
>> Subject: [PATCH 2/2] cdc-wdm: fix memory leak
>>
>> cleanup() is not called if the last close() comes after
>> disconnect(). That leads to a memory leak. Rectified
>> by checking for an earlier disconnect() in release()
>>
>> Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
>> ---
>> drivers/usb/class/cdc-wdm.c | 2 ++
>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
>> index 0209b46..6bf1a40 100644
>> --- a/drivers/usb/class/cdc-wdm.c
>> +++ b/drivers/usb/class/cdc-wdm.c
>> @@ -625,6 +625,8 @@ static int wdm_release(struct inode *inode, struct file *file)
>> kill_urbs(desc);
>> if (!test_bit(WDM_DISCONNECTING, &desc->flags))
>> desc->manage_power(desc->intf, 0);
>> + else
>> + cleanup(desc);
>> }
>> mutex_unlock(&wdm_mutex);
>> return 0;
>
> Looks good to me.
BTW, would it make sense to add a couple of debug messages to make it
easier to follow the program flow here? Something like this maybe?:
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index da13bbc..b6010ae 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -623,10 +623,12 @@ static int wdm_release(struct inode *inode, struct file *file)
if (!desc->count) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
kill_urbs(desc);
- if (!test_bit(WDM_DISCONNECTING, &desc->flags))
+ if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
desc->manage_power(desc->intf, 0);
- else
+ } else {
+ dev_dbg(&desc->intf->dev, "%s: device gone - cleaning up\n", __func__);
cleanup(desc);
+ }
}
mutex_unlock(&wdm_mutex);
return 0;
@@ -900,6 +902,8 @@ static void wdm_disconnect(struct usb_interface *intf)
mutex_unlock(&desc->rlock);
if (!desc->count)
cleanup(desc);
+ else
+ dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
mutex_unlock(&wdm_mutex);
}
Bjørn
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