4 files changed, 39 insertions, 5 deletions
diff --git a/source/blender/blenlib/BLI_lazy_threading.hh b/source/blender/blenlib/BLI_lazy_threading.hh
index b5a15919c89..4d04fe9e908 100644
--- a/source/blender/blenlib/BLI_lazy_threading.hh
+++ b/source/blender/blenlib/BLI_lazy_threading.hh
@@ -80,4 +80,15 @@ class HintReceiver {
   ~HintReceiver();
 };
 
+/**
+ * Used to make sure that lazy-threading hints don't propagate through task isolation. This is
+ * necessary to avoid deadlocks when isolated regions are used together with e.g. task pools. For
+ * more info see the comment on #BLI_task_isolate.
+ */
+class ReceiverIsolation {
+ public:
+  ReceiverIsolation();
+  ~ReceiverIsolation();
+};
+
 }  // namespace blender::lazy_threading
diff --git a/source/blender/blenlib/BLI_task.hh b/source/blender/blenlib/BLI_task.hh
index 9f9a57be634..e7d9a21439a 100644
--- a/source/blender/blenlib/BLI_task.hh
+++ b/source/blender/blenlib/BLI_task.hh
@@ -129,6 +129,7 @@ void parallel_invoke(const bool use_threading, Functions &&...functions)
 template<typename Function> void isolate_task(const Function &function)
 {
 #ifdef WITH_TBB
+  lazy_threading::ReceiverIsolation isolation;
   tbb::this_task_arena::isolate(function);
 #else
   function();
diff --git a/source/blender/blenlib/intern/lazy_threading.cc b/source/blender/blenlib/intern/lazy_threading.cc
index 803fd81a96d..4f6d3a75ecc 100644
--- a/source/blender/blenlib/intern/lazy_threading.cc
+++ b/source/blender/blenlib/intern/lazy_threading.cc
@@ -1,30 +1,50 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include "BLI_lazy_threading.hh"
+#include "BLI_stack.hh"
 #include "BLI_vector.hh"
 
 namespace blender::lazy_threading {
 
 /**
- * This is a #RawVector so that it can be destructed after Blender checks for memory leaks.
+ * This uses a "raw" stack and vector so that it can be destructed after Blender checks for memory
+ * leaks. A new list of receivers is created whenever an isolated region is entered to avoid
+ * deadlocks.
  */
-thread_local RawVector<FunctionRef<void()>, 0> hint_receivers;
+using HintReceivers = RawStack<RawVector<FunctionRef<void()>, 0>, 0>;
+thread_local HintReceivers hint_receivers = []() {
+  HintReceivers receivers;
+  /* Make sure there is always at least one vector. */
+  receivers.push_as();
+  return receivers;
+}();
 
 void send_hint()
 {
-  for (const FunctionRef<void()> &fn : hint_receivers) {
+  for (const FunctionRef<void()> &fn : hint_receivers.peek()) {
     fn();
   }
 }
 
 HintReceiver::HintReceiver(const FunctionRef<void()> fn)
 {
-  hint_receivers.append(fn);
+  hint_receivers.peek().append(fn);
 }
 
 HintReceiver::~HintReceiver()
 {
-  hint_receivers.pop_last();
+  hint_receivers.peek().pop_last();
+}
+
+ReceiverIsolation::ReceiverIsolation()
+{
+  hint_receivers.push_as();
+}
+
+ReceiverIsolation::~ReceiverIsolation()
+{
+  BLI_assert(hint_receivers.peek().is_empty());
+  hint_receivers.pop();
 }
 
 }  // namespace blender::lazy_threading
diff --git a/source/blender/blenlib/intern/task_scheduler.cc b/source/blender/blenlib/intern/task_scheduler.cc
index 1f7747453c1..5b056df78b4 100644
--- a/source/blender/blenlib/intern/task_scheduler.cc
+++ b/source/blender/blenlib/intern/task_scheduler.cc
@@ -8,6 +8,7 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "BLI_lazy_threading.hh"
 #include "BLI_task.h"
 #include "BLI_threads.h"
 
@@ -67,6 +68,7 @@ int BLI_task_scheduler_num_threads()
 void BLI_task_isolate(void (*func)(void *userdata), void *userdata)
 {
 #ifdef WITH_TBB
+  blender::lazy_threading::ReceiverIsolation isolation;
   tbb::this_task_arena::isolate([&] { func(userdata); });
 #else
   func(userdata);