non-reentrant trylock in maybe_destroy_plan

Author: stevengj

src/fft.jl

@@ -275,6 +275,10 @@ unsafe_destroy_plan(plan::FFTWPlan{<:fftwSingle}) =
 const deferred_destroy_lock = ReentrantLock() # lock protecting the deferred_destroy_plans list
 const deferred_destroy_plans = FFTWPlan[]
 
+# hack to get non-reentrant lock, which is necessary to prevent GC running in the
+# same task that acquired fftwlock to use deferred_destroy_plans in maybe_destroy_plan.
+trylock_nonreentrant(rl::ReentrantLock) = current_task() !== rl.locked_by && trylock(rl)
+
 function destroy_deferred()
     try
         lock(deferred_destroy_lock)
@@ -302,7 +306,7 @@ function maybe_destroy_plan(plan::FFTWPlan)
         # (race to avoid: trylock == false, other thread unlocks and calls destroy_deferred,
         #                 then we push a deferred plan that may never get freed)
         lock(deferred_destroy_lock)
-        if trylock(fftwlock)
+        if trylock_nonreentrant(fftwlock)
             try
                 unsafe_destroy_plan(plan)
             finally