Fix T45199 crash when editing material nodes.

Issue is data race between preview job and GPU nodetree evaluation when
localizing the nodetree. Data race happens due to localizations doing
overrides on original nodes' new_node variable.

Solution here could probably be to use a hash for mapping of old to new
nodes but will prefer simple brute force lock for now.

1 files changed, 34 insertions, 15 deletions

diff --git a/source/blender/blenkernel/intern/node.c b/source/blender/blenkernel/intern/node.c
index c1fa6c55d59..8ac0a8a31f6 100644
--- a/source/blender/blenkernel/intern/node.c
+++ b/source/blender/blenkernel/intern/node.c
@@ -62,6 +62,7 @@
 #include "BKE_node.h"
 
 #include "BLI_ghash.h"
+#include "BLI_threads.h"
 #include "RNA_access.h"
 #include "RNA_define.h"
 
@@ -287,6 +288,7 @@ void ntreeSetTypes(const struct bContext *C, bNodeTree *ntree)
 static GHash *nodetreetypes_hash = NULL;
 static GHash *nodetypes_hash = NULL;
 static GHash *nodesockettypes_hash = NULL;
+static SpinLock spin;
 
 bNodeTreeType *ntreeTypeFind(const char *idname)
 {
@@ -1131,6 +1133,8 @@ static bNodeTree *ntreeCopyTree_internal(bNodeTree *ntree, Main *bmain, bool ski
 
 	/* in case a running nodetree is copied */
 	newtree->execdata = NULL;
+
+	newtree->duplilock = NULL;
 	
 	BLI_listbase_clear(&newtree->nodes);
 	BLI_listbase_clear(&newtree->links);
@@ -1775,6 +1779,9 @@ void ntreeFreeTree_ex(bNodeTree *ntree, const bool do_id_user)
 	if (ntree->previews) {
 		BKE_node_instance_hash_free(ntree->previews, (bNodeInstanceValueFP)BKE_node_preview_free);
 	}
+
+	if (ntree->duplilock)
+		BLI_mutex_free(ntree->duplilock);
 	
 	/* if ntree is not part of library, free the libblock data explicitly */
 	for (tntree = G.main->nodetree.first; tntree; tntree = tntree->id.next)
@@ -1962,56 +1969,67 @@ bNodeTree *ntreeLocalize(bNodeTree *ntree)
 	if (ntree) {
 		bNodeTree *ltree;
 		bNode *node;
-		
+		AnimData *adt;
+
 		bAction *action_backup = NULL, *tmpact_backup = NULL;
-		
+
+		BLI_spin_lock(&spin);
+		if (!ntree->duplilock) {
+			ntree->duplilock = BLI_mutex_alloc();
+		}
+		BLI_spin_unlock(&spin);
+
+		BLI_mutex_lock(ntree->duplilock);
+
 		/* Workaround for copying an action on each render!
 		 * set action to NULL so animdata actions don't get copied */
-		AnimData *adt = BKE_animdata_from_id(&ntree->id);
-	
+		adt = BKE_animdata_from_id(&ntree->id);
+
 		if (adt) {
 			action_backup = adt->action;
 			tmpact_backup = adt->tmpact;
-	
+
 			adt->action = NULL;
 			adt->tmpact = NULL;
 		}
-	
+
 		/* Make full copy.
 		 * Note: previews are not copied here.
 		 */
 		ltree = ntreeCopyTree_internal(ntree, G.main, true, false, false, false);
 		ltree->flag |= NTREE_IS_LOCALIZED;
-		
+
 		for (node = ltree->nodes.first; node; node = node->next) {
 			if (node->type == NODE_GROUP && node->id) {
 				node->id = (ID *)ntreeLocalize((bNodeTree *)node->id);
 			}
 		}
-		
+
 		if (adt) {
 			AnimData *ladt = BKE_animdata_from_id(&ltree->id);
-	
+
 			adt->action = ladt->action = action_backup;
 			adt->tmpact = ladt->tmpact = tmpact_backup;
-	
+
 			if (action_backup) action_backup->id.us++;
 			if (tmpact_backup) tmpact_backup->id.us++;
-			
+
 		}
 		/* end animdata uglyness */
-	
+
 		/* ensures only a single output node is enabled */
 		ntreeSetOutput(ntree);
-	
+
 		for (node = ntree->nodes.first; node; node = node->next) {
 			/* store new_node pointer to original */
 			node->new_node->new_node = node;
 		}
-	
+
 		if (ntree->typeinfo->localize)
 			ntree->typeinfo->localize(ltree, ntree);
-	
+
+		BLI_mutex_unlock(ntree->duplilock);
+
 		return ltree;
 	}
 	else
@@ -3630,6 +3648,7 @@ void init_nodesystem(void)
 	nodetreetypes_hash = BLI_ghash_str_new("nodetreetypes_hash gh");
 	nodetypes_hash = BLI_ghash_str_new("nodetypes_hash gh");
 	nodesockettypes_hash = BLI_ghash_str_new("nodesockettypes_hash gh");
+	BLI_spin_init(&spin);
 
 	register_undefined_types();