Fix module loadex command crash due to invalid config (#13653)

Fix to https://github.com/redis/redis/issues/13650

providing an invalid config to a module with datatype crashes when redis
tries to unload the module due to the invalid config

---------

Co-authored-by: debing.sun <debing.sun@redis.com>

src/module.c

@@ -12262,7 +12262,7 @@ int moduleLoad(const char *path, void **module_argv, int module_argc, int is_loa
     }
 
     if (post_load_err) {
-        moduleUnload(ctx.module->name, NULL);
+        serverAssert(moduleUnload(ctx.module->name, NULL, 1) == C_OK);
         moduleFreeContext(&ctx);
         return C_ERR;
     }
@@ -12278,14 +12278,17 @@ int moduleLoad(const char *path, void **module_argv, int module_argc, int is_loa
 
 /* Unload the module registered with the specified name. On success
  * C_OK is returned, otherwise C_ERR is returned and errmsg is set
- * with an appropriate message. */
-int moduleUnload(sds name, const char **errmsg) {
+ * with an appropriate message.
+ * Only forcefully unload this module, passing forced_unload != 0, 
+ * if it is certain that it has not yet been in use (e.g., immediate
+ * unload on failed load). */
+int moduleUnload(sds name, const char **errmsg, int forced_unload) {
     struct RedisModule *module = dictFetchValue(modules,name);
 
     if (module == NULL) {
         *errmsg = "no such module with that name";
         return C_ERR;
-    } else if (listLength(module->types)) {
+    } else if (listLength(module->types) && !forced_unload) {
         *errmsg = "the module exports one or more module-side data "
                   "types, can't unload";
         return C_ERR;
@@ -13078,7 +13081,7 @@ NULL
 
     } else if (!strcasecmp(subcmd,"unload") && c->argc == 3) {
         const char *errmsg = NULL;
-        if (moduleUnload(c->argv[2]->ptr, &errmsg) == C_OK)
+        if (moduleUnload(c->argv[2]->ptr, &errmsg, 0) == C_OK)
             addReply(c,shared.ok);
         else {
             if (errmsg == NULL) errmsg = "operation not possible.";

src/server.h

@@ -2469,7 +2469,7 @@ void moduleInitModulesSystem(void);
 void moduleInitModulesSystemLast(void);
 void modulesCron(void);
 int moduleLoad(const char *path, void **argv, int argc, int is_loadex);
-int moduleUnload(sds name, const char **errmsg);
+int moduleUnload(sds name, const char **errmsg, int forced_unload);
 void moduleLoadFromQueue(void);
 int moduleGetCommandKeysViaAPI(struct redisCommand *cmd, robj **argv, int argc, getKeysResult *result);
 int moduleGetCommandChannelsViaAPI(struct redisCommand *cmd, robj **argv, int argc, getKeysResult *result);

tests/modules/datatype.c

@@ -312,3 +312,12 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
 
     return REDISMODULE_OK;
 }
+
+int RedisModule_OnUnload(RedisModuleCtx *ctx) {
+    REDISMODULE_NOT_USED(ctx);
+    if (datatype) {
+        RedisModule_Free(datatype);
+        datatype = NULL;
+    }
+    return REDISMODULE_OK;
+}

tests/unit/moduleapi/datatype.tcl

@@ -1,6 +1,11 @@
 set testmodule [file normalize tests/modules/datatype.so]
 
 start_server {tags {"modules"}} {
+    test {DataType: test loadex with invalid config} {
+        catch { r module loadex $testmodule CONFIG invalid_config 1 } e
+        assert_match {*ERR Error loading the extension*} $e
+    }
+
     r module load $testmodule
 
     test {DataType: Test module is sane, GET/SET work.} {