In the Linux kernel, the following vulnerability has been resolved:kprobes: Fix possible use-after-free issue on kprobe registrationWhen unloading a module, its state is changing MODULE_STATE_LIVE -> MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will takea time. `is_module_text_address()` and `__module_text_address()`works with MODULE_STATE_LIVE and MODULE_STATE_GOING.If we use `is_module_text_address()` and `__module_text_address()`separately, there is a chance that the first one is succeeded but thenext one is failed because module->state becomes MODULE_STATE_UNFORMEDbetween those operations.In `check_kprobe_address_safe()`, if the second `__module_text_address()`is failed, that is ignored because it expected a kernel_text address.But it may have failed simply because module->state has been changedto MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modifynon-exist module text address (use-after-free).To fix this problem, we should not use separated `is_module_text_address()`and `__module_text_address()`, but use only `__module_text_address()`once and do `try_module_get(module)` which is only available withMODULE_STATE_LIVE.
CWE-416 Use After Free