Avi Kivity edcd346d83 thread: fix thread-created-within-thread ...

The thread switching code assumed that we will always switch out of a
thread due to being blocked on an unavailable future.  This allows
the core to store the blocked thread's context in the synthetic
continuation chained to that future (which switched back to that thread).

That assumption failed in one place: when we create a thread from within a
thread.  In that case we switch to the new thread immediately, but forget
all about the old thread.  We never come back to the old thread, and anything
that depends on it hangs.

Fix by creating a linked list of active thread contexts.  These are all
threads that have been "preempted" by the act of creating a new thread,
terminated by the main, unthreaded, reactor context.  This gives us a place
to store those threads and we come back to them and continue where we left
off.

Reported by Pekka.

2015-06-16 17:04:02 +03:00

6.3 KiB

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