Oliver Neukum wrote:
> Am Donnerstag, 15. Februar 2007 19:35 schrieb Greg KH:
>> On Thu, Feb 15, 2007 at 01:51:31PM +0100, Oliver Neukum wrote:
>>> Am Donnerstag, 15. Februar 2007 00:31 schrieb [EMAIL PROTECTED]:
>>>> +??????????????dev = (struct iowarrior *)file->private_data;
>>>> +
>>>> +??????????????/* verify that the device wasn't unplugged */
>>>> +??????????????if (dev == NULL || !dev->present) {
>>>> +??????????????????????????????retval = -ENODEV;
>>>> +??????????????????????????????goto exit;
>>>> +??????????????}
>>> This needs the lock to be taken. You've a race condition that allows
>>> URBs to be submitted for an interface that somebody else may have
>>> claimed.
>> Which lock? The disconnect_sem one?
>
> mutex_lock(&dev->mutex);
> The same that is already taken in the ioctl handler.
One stupid question: Suppose we're in iowarrior_read(), got a pointer on
private_data, but haven't taken the mutex yet. iowarrior_release() is
called, locks the mutex, decrements the opened counter to 0, and then
call iowarrior_delete(). iowarrior_read() resumes, and tries to grab
dev->mutex, but at that point dev is NULL, and we oops. How is that case
handled ?
Cheers,
Samuel.
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