Hello, In hurd/proc/mgt.c:S_proc_exception_raise(), the proc server forwards the message to the target thread by calling proc_exception_raise(). In error cases it returns 0, which msgserver then replies to the requester. However, if for instance proc_exception_raise() managed to send the message but failed on reception, the reply port will have been consumed already, and msgserver erroneously use/deallocate it, so in such cases we need to return MIG_NO_REPLY since we won't be able to send a reply anyway. I have to say I'm unable to determine in which error conditions we need to do that. The one that I encountered was MACH_RCV_INVALID_NAME.
Samuel
