MINOR: threads: add a thread_harmless_end() version that doesn't wait
thread_harmless_end() needs to wait for rdv_requests to disappear so
that we're certain to respect a harmless promise that possibly allowed
another thread to proceed under isolation. But this doesn't work in a
signal handler because a thread could be interrupted by the debug
handler while already waiting for isolation and with rdv_request>0.
As such this function could cause a deadlock in such a signal handler.
Let's implement a specific variant for this, thread_harmless_end_sig(),
that just resets the thread's bit and doesn't wait. It must of course
not be used past a check point that would allow the isolation requester
to return and see the thread as temporarily harmless then turning back
on its promise.
This will be needed to fix a race in the debug handler.
1 file changed