IOS ui lockup

[Dave Dyer]

I'm tracking the IOS UI lockup I reported in another thread long ago, but have some new data, because
this time I was running the locked app under the ios simulator.

The EDT thread is marked ->threadBlockedByGC and is waiting at the end of monitorEnter.
This accounts for the UI lockup symptom.

The GC thread is waiting in codename1GCMark, waiting for thread 17 to be inactive.

Thread 17 doesn't exist.  Its threadData table seems to be in good repair, but there
is no thread 17 in allThreads

threadsToDelete is all nulls.

... with my imperfect understanding of the threading and gc environment, it looks like
thread 17 went away while the GC was waiting for it, and no one told the GC.

[Shai Almog]

You can copy and paste the stack traces of all the threads in plain text and file an issue on the deadlock. It's possible there is a race condition here that we missed.

[Dave Dyer]

stack traces are long gone, but were uninteresting.  They were all just blocked at the
exit of a monitor.  The interesting point was that the gc was waiting forever for a process
that no longer exists in allThreads

[Shai Almog]

So this isn't something that's reproducible?

[Dave Dyer]

No, it's in the "rare" category.  This was the first time I saw it while running
under the iphone simulator, so the first time I was able to get any useful
information at all.  My current experiments with processes and gc are
an attempt to induce it.