[phobos] std.parallelism unit test hang

[Brad Roberts]

Could be the same as one of the previous threads.  Sorry for being a little lazy (it's that kinda weekend):

I just noticed that the phobos linux 64/32 build had been running for almost 10 hours (I guess I need to add some
timeout logic still).  I attached gdb to get a stack trace:

#0  0x55573425 in __kernel_vsyscall ()
#1  0x555b0469 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
#2  0x555ab659 in _L_lock_835 () from /lib32/libpthread.so.0
#3  0x555ab4eb in __pthread_mutex_lock (mutex=0x8139264) at pthread_mutex_lock.c:82
#4  0x080f4065 in _d_criticalenter ()
#5  0x080d4ea3 in std.parallelism.__unittest2() ()
#6  0x080ed3a5 in
std.parallelism.__T19ParallelForeachTaskTS3std5range13__T4iotaTiTiZ4iota6ResultTDFKiZiZ.ParallelForeachTask.impl() ()
#7  0x080d3253 in std.parallelism.AbstractTask.job() ()
#8  0x080d3523 in std.parallelism.TaskPool.tryDeleteExecute() ()
#9  0x080ed1e1 in
std.parallelism.__T19ParallelForeachImplTS3std5range13__T4iotaTiTiZ4iota6ResultTDFKiZiZ.ParallelForeachImpl.__T17ResubmittingTasksZ.submitAndExecute()
()
#10 0x080e44a2 in std.parallelism.__T15ParallelForeachTS3std5range13__T4iotaTiTiZ4iota6ResultZ.ParallelForeach.opApply() ()
#11 0x080d49db in std.parallelism.__unittest2() ()
#12 0x080edba9 in std.parallelism.__modtest() ()
#13 0x080ff9dc in core.runtime.runModuleUnitTests() ()
#14 0x080efca2 in object.ModuleInfo.opApply() ()
#15 0x080ff8f7 in runModuleUnitTests ()
#16 0x080f4980 in rt.dmain2.main() ()
#17 0x080f45e8 in rt.dmain2.main() ()
#18 0x080f4594 in main ()

Without having looked at the code, the stack suggests a recursive call resulting in a deadlock.  Notice frame 11 and 5
are in the same function.

Have fun with it.

Later,
Brad