bugfix: we now only recycle light threads which are "entry threads" otherwise it is not safe to recycle user created threads since we have no idea whether the user may still hold refs to them.

Author: agentzh

src/ngx_http_lua_uthread.c

@@ -91,6 +91,8 @@ ngx_http_lua_uthread_spawn(lua_State *L)
     coctx->parent_co_ctx = ctx->cur_co_ctx;
     ctx->cur_co_ctx = coctx;
 
+    ngx_http_lua_attach_co_ctx_to_L(coctx->co, coctx);
+
     ngx_http_lua_probe_user_thread_spawn(r, L, coctx->co);
 
     dd("yielding with arg %s, top=%d, index-1:%s", luaL_typename(L, -1),

src/ngx_http_lua_util.c

@@ -422,7 +422,10 @@ ngx_http_lua_del_thread(ngx_http_request_t *r, lua_State *L,
 #ifdef HAVE_LUA_RESETTHREAD
     lmcf = ngx_http_get_module_main_conf(r, ngx_http_lua_module);
 
-    if (L == lmcf->lua && !ngx_queue_empty(&lmcf->free_lua_threads)) {
+    if (ctx != NULL
+        && coctx->co == ctx->entry_co_ctx.co
+        && L == lmcf->lua && !ngx_queue_empty(&lmcf->free_lua_threads))
+    {
         lua_resetthread(L, coctx->co);
         q = ngx_queue_head(&lmcf->free_lua_threads);
         tref = ngx_queue_data(q, ngx_http_lua_thread_ref_t, queue);

src/ngx_http_lua_util.h

@@ -560,8 +560,14 @@ ngx_http_lua_free_thread(ngx_http_request_t *r, lua_State *L, int co_ref,
 #ifdef HAVE_LUA_RESETTHREAD
     ngx_queue_t                 *q;
     ngx_http_lua_thread_ref_t   *tref ;
+    ngx_http_lua_ctx_t          *ctx;
 
-    if (L == lmcf->lua && !ngx_queue_empty(&lmcf->free_lua_threads)) {
+    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
+    if (ctx != NULL
+        && L == ctx->entry_co_ctx.co
+        && L == lmcf->lua
+        && !ngx_queue_empty(&lmcf->free_lua_threads))
+    {
         lua_resetthread(L, co);
 
         q = ngx_queue_head(&lmcf->free_lua_threads);