riscv: module: remove relocation_head rel_entry member allocation

relocation_head's list_head member, rel_entry, doesn't need to be
allocated, its storage can just be part of the allocated relocation_head.
Remove the pointer which allows to get rid of the allocation as well as
an existing memory leak found by Kai Zhang using kmemleak.

Fixes: 8fd6c51 ("riscv: Add remaining module relocations")
Reported-by: Kai Zhang <zhangkai@iscas.ac.cn>
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20241128081636.3620468-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/module.c

@@ -23,7 +23,7 @@ struct used_bucket {
 
 struct relocation_head {
 	struct hlist_node node;
-	struct list_head *rel_entry;
+	struct list_head rel_entry;
 	void *location;
 };
 
@@ -634,7 +634,7 @@ process_accumulated_relocations(struct module *me,
 			location = rel_head_iter->location;
 			list_for_each_entry_safe(rel_entry_iter,
 						 rel_entry_iter_tmp,
-						 rel_head_iter->rel_entry,
+						 &rel_head_iter->rel_entry,
 						 head) {
 				curr_type = rel_entry_iter->type;
 				reloc_handlers[curr_type].reloc_handler(
@@ -704,16 +704,7 @@ static int add_relocation_to_accumulate(struct module *me, int type,
 			return -ENOMEM;
 		}
 
-		rel_head->rel_entry =
-			kmalloc(sizeof(struct list_head), GFP_KERNEL);
-
-		if (!rel_head->rel_entry) {
-			kfree(entry);
-			kfree(rel_head);
-			return -ENOMEM;
-		}
-
-		INIT_LIST_HEAD(rel_head->rel_entry);
+		INIT_LIST_HEAD(&rel_head->rel_entry);
 		rel_head->location = location;
 		INIT_HLIST_NODE(&rel_head->node);
 		if (!current_head->first) {
@@ -722,7 +713,6 @@ static int add_relocation_to_accumulate(struct module *me, int type,
 
 			if (!bucket) {
 				kfree(entry);
-				kfree(rel_head->rel_entry);
 				kfree(rel_head);
 				return -ENOMEM;
 			}
@@ -735,7 +725,7 @@ static int add_relocation_to_accumulate(struct module *me, int type,
 	}
 
 	/* Add relocation to head of discovered rel_head */
-	list_add_tail(&entry->head, rel_head->rel_entry);
+	list_add_tail(&entry->head, &rel_head->rel_entry);
 
 	return 0;
 }