[Bf-blender-cvs] [69c389fd634] blender-v2.79-release: Cycles: Guard memcpy to potentially re-allocating memory with lock

[Sergey Sharybin]

Commit: 69c389fd63432d164f3ceaaf3b408e7d76504a3e
Author: Sergey Sharybin
Date:   Mon Aug 14 14:55:47 2017 +0200
Branches: blender-v2.79-release
https://developer.blender.org/rB69c389fd63432d164f3ceaaf3b408e7d76504a3e

Cycles: Guard memcpy to potentially re-allocating memory with lock

Basically, make re-alloc and memcpy from the same lock, otherwise one
thread might be re-allocating thread while another one is trying to
copy data there.

Reported by Mohamed Sakr in IRC, thanks!

===================================================================

M	intern/cycles/bvh/bvh_build.cpp

===================================================================

diff --git a/intern/cycles/bvh/bvh_build.cpp b/intern/cycles/bvh/bvh_build.cpp
index 1880964355c..224dcbaf3fc 100644
--- a/intern/cycles/bvh/bvh_build.cpp
+++ b/intern/cycles/bvh/bvh_build.cpp
@@ -1040,7 +1040,6 @@ BVHNode* BVHBuild::create_leaf_node(const BVHRange& range,
 		 */
 		start_index = spatial_free_index;
 		spatial_free_index += range.size();
-
 		/* Extend an array when needed. */
 		const size_t range_end = start_index + range.size();
 		if(prim_type.size() < range_end) {
@@ -1066,8 +1065,6 @@ BVHNode* BVHBuild::create_leaf_node(const BVHRange& range,
 				prim_time.resize(range_end);
 			}
 		}
-		spatial_spin_lock.unlock();
-
 		/* Perform actual data copy. */
 		if(new_leaf_data_size > 0) {
 			memcpy(&prim_type[start_index], &local_prim_type[0], new_leaf_data_size);
@@ -1077,6 +1074,7 @@ BVHNode* BVHBuild::create_leaf_node(const BVHRange& range,
 				memcpy(&prim_time[start_index], &local_prim_time[0], sizeof(float2)*num_new_leaf_data);
 			}
 		}
+		spatial_spin_lock.unlock();
 	}
 	else {
 		/* For the regular BVH builder we simply copy new data starting at the