Hello: Question: The vm_operations_struct structure contains lots of callback pointers. Is there any mechanism to prevent the callback routines and the structure itself being unloaded from memory (if they are built into modules) while the relevant VMAs are still in use? Consider a simple example: A user program calls mmap(2) on a device file. Later on, the file is closed and the device driver's module is unloaded. But until munmap(2) is called or the user program exits, the memory mapping and the corresponding VMA will remain in existence. (The man page for munmap specifically says "closing the file descriptor does not unmap the region".) Thus when the user program does do an munmap(), the callback to vma->vm_ops->close will reference nonexistent memory and cause an oops. Normally this sort of thing is prevented by try_module_get(...->owner). But vm_operations_struct doesn't include a .owner field. Am I missing something here? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
