In the Linux kernel, the following vulnerability has been resolved:
freezer,umh: Fix callusermodehelper_exec() vs SIGKILL
Tetsuo-San noted that commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") broke callusermodehelperexec() for the KILLABLE case.
Specifically it was missed that the second, unconditional, waitforcompletion() was not optional and ensures the on-stack completion is unused before going out-of-scope.