Tue Dec 21 03:58:07 PST 2010 Simon Marlow <marlo...@gmail.com>
* boundTaskExiting: don't set task->stopped unless this is the last call
(#4850)
The bug in this case was that we had a worker thread making a foreign
call which invoked a callback (in this case it was performGC, I
think). When the callback ended, boundTaskExiting() was setting
task->stopped, but the Task is now per-OS-thread, so it is shared by
the worker that made the original foreign call. When the foreign call
returned, because task->stopped was set, the worker was not placed on
the queue of spare workers. Somehow the worker woke up again, and
found the spare_workers queue empty, which lead to a crash.
Two bugs here: task->stopped should not have been set by
boundTaskExiting (this broke when I split the Task and InCall structs,
in 6.12.2), and releaseCapabilityAndQueueWorker() should not be
testing task->stopped anyway, because it should only ever be called
when task->stopped is false (this is now an assertion).
M ./rts/Task.c -2 +8
View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20101221115807-12142-f2cc427fa92ff2d4737a72446298acb68af3f572.gz
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