ggml: fix ggml_graph_cpy undefined behavior (#943)

diff --git a/include/ggml.h b/include/ggml.h
index b11d047aeda7d057f74f9b606e8d2f837e44a16c..2d381f91c889bcdaaef05120b554e05d5616ab86 100644 (file)
--- a/include/ggml.h
+++ b/include/ggml.h
@@ -651,8 +651,8 @@ extern "C" {
 
     struct ggml_hash_set {
         size_t size;
-        ggml_bitset_t * used;
-        struct ggml_tensor ** keys;
+        ggml_bitset_t * used;       // whether or not the keys are in use i.e. set
+        struct ggml_tensor ** keys; // actual tensors in the set, keys[i] is only defined if ggml_bitset_get(used, i)
     };
 
     // computation graph

diff --git a/src/ggml.c b/src/ggml.c
index 3b059ab6db07ebcad4b114f5a1cba9270982e378..1e0dde6e8bb64db933640e930e13f05720bfc4e8 100644 (file)
--- a/src/ggml.c
+++ b/src/ggml.c
@@ -18764,7 +18764,8 @@ void ggml_graph_cpy(struct ggml_cgraph * src, struct ggml_cgraph * dst) {
     }
 
     for (size_t i = 0; i < src->visited_hash_set.size; ++i) {
-        if (src->visited_hash_set.keys[i]) {
+        // copy all hashset keys (tensors) that are in use
+        if (ggml_bitset_get(src->visited_hash_set.used, i)) {
             ggml_hash_insert(&dst->visited_hash_set, src->visited_hash_set.keys[i]);
         }
     }