some dbgext got caught in a readvirtual loop, blindly got out of it using:
dbgeng+0x951ec // (waitforpacket) clear zf to break loop
dbgeng+0x95aa6 // (sendreceivemanip) set loop counter to 0x10
dbgeng+0x8c65f // (readvirtual) skip over this dispatch, then set eax to 0
dbgeng+0x92cfd // flushcallbacks, not important windbg dbgeng readvirtual