Separate context freeing from task freeing in threaded particle updates

to prevent double-freeing/invalid mem access.

This can happen with the "virtual parents" feature, which generates both
parent and child paths. Each task free function also freed the shared
context, leading to double freeing.

4 files changed, 18 insertions, 12 deletions

diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index 71805160927..4c6b0cc0dac 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -350,6 +350,7 @@ void psys_get_dupli_path_transform(struct ParticleSimulationData *sim, struct Pa
                                    struct ParticleCacheKey *cache, float mat[4][4], float *scale);
 
 void psys_thread_context_init(struct ParticleThreadContext *ctx, struct ParticleSimulationData *sim);
+void psys_thread_context_free(struct ParticleThreadContext *ctx);
 void psys_tasks_create(struct ParticleThreadContext *ctx, int totpart, struct ParticleTask **r_tasks, int *r_numtasks);
 void psys_tasks_free(struct ParticleTask *tasks, int numtasks);
 
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index aa62b7778c9..847cae9f0fc 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -2587,6 +2587,8 @@ void psys_cache_child_paths(ParticleSimulationData *sim, float cfra, int editupd
 	
 	psys_tasks_free(tasks_parent, numtasks_parent);
 	psys_tasks_free(tasks_child, numtasks_child);
+	
+	psys_thread_context_free(&ctx);
 }
 
 /* figure out incremental rotations along path starting from unit quat */
diff --git a/source/blender/blenkernel/intern/particle_distribute.c b/source/blender/blenkernel/intern/particle_distribute.c
index 90338e96945..7a422abae47 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -1140,6 +1140,8 @@ static void distribute_particles_on_dm(ParticleSimulationData *sim, int from)
 		ctx.dm->release(ctx.dm);
 	
 	psys_tasks_free(tasks, numtasks);
+	
+	psys_thread_context_free(&ctx);
 }
 
 /* ready for future use, to emit particles without geometry */
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 93eb273fc00..6e7e341e1cc 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -471,13 +471,24 @@ void psys_tasks_create(ParticleThreadContext *ctx, int totpart, ParticleTask **r
 
 void psys_tasks_free(ParticleTask *tasks, int numtasks)
 {
-	ParticleThreadContext *ctx;
 	int i;
 	
 	if (numtasks == 0)
 		return;
 	
-	ctx = tasks[0].ctx;
+	/* threads */
+	for (i = 0; i < numtasks; ++i) {
+		if (tasks[i].rng)
+			BLI_rng_free(tasks[i].rng);
+		if (tasks[i].rng_path)
+			BLI_rng_free(tasks[i].rng_path);
+	}
+
+	MEM_freeN(tasks);
+}
+
+void psys_thread_context_free(ParticleThreadContext *ctx)
+{
 	/* path caching */
 	if (ctx->vg_length)
 		MEM_freeN(ctx->vg_length);
@@ -506,16 +517,6 @@ void psys_tasks_free(ParticleTask *tasks, int numtasks)
 	if (ctx->seams) MEM_freeN(ctx->seams);
 	//if (ctx->vertpart) MEM_freeN(ctx->vertpart);
 	BLI_kdtree_free(ctx->tree);
-
-	/* threads */
-	for (i = 0; i < numtasks; ++i) {
-		if (tasks[i].rng)
-			BLI_rng_free(tasks[i].rng);
-		if (tasks[i].rng_path)
-			BLI_rng_free(tasks[i].rng_path);
-	}
-
-	MEM_freeN(tasks);
 }
 
 static void initialize_particle_texture(ParticleSimulationData *sim, ParticleData *pa, int p)