Fix race condition

Exposed when checking on T44871

1 files changed, 4 insertions, 0 deletions

diff --git a/source/blender/blenlib/intern/threads.c b/source/blender/blenlib/intern/threads.c
index a404f46a6e2..50295954192 100644
--- a/source/blender/blenlib/intern/threads.c
+++ b/source/blender/blenlib/intern/threads.c
@@ -199,6 +199,7 @@ void BLI_init_threads(ListBase *threadbase, void *(*do_thread)(void *), int tot)
 		}
 	}
 	
+	BLI_spin_lock(&_malloc_lock);
 	if (thread_levels == 0) {
 		MEM_set_lock_callback(BLI_lock_malloc_thread, BLI_unlock_malloc_thread);
 
@@ -211,6 +212,7 @@ void BLI_init_threads(ListBase *threadbase, void *(*do_thread)(void *), int tot)
 	}
 
 	thread_levels++;
+	BLI_spin_unlock(&_malloc_lock);
 }
 
 /* amount of available threads */
@@ -329,9 +331,11 @@ void BLI_end_threads(ListBase *threadbase)
 		BLI_freelistN(threadbase);
 	}
 
+	BLI_spin_lock(&_malloc_lock);
 	thread_levels--;
 	if (thread_levels == 0)
 		MEM_set_lock_callback(NULL, NULL);
+	BLI_spin_unlock(&_malloc_lock);
 }
 
 /* System Information */