thread_single(P_TOTAL_STOP): set single-threading thread runnable

[kib]

Summary

as last resort in ast_suspend(), since we might be the last thread going
in suspended state and the single-threading thread already off the cpu.

Reported by:    pho

[markj]

sys/kern/kern_thread.c

535

538

549

For other stop types, thread_suspend_check() is responsible for waking up the initiator with thread_unsuspend_one(). Why do we not handle the ALLSTOP case in thread_suspend_check() too?

[kib]

Too naive, unfortunately.