From 23d5f828c687a2d97f6b19a5317a760c0cc73d4d Mon Sep 17 00:00:00 2001
From: Konstantin Osipov <kostja@tarantool.org>
Date: Fri, 22 Mar 2013 18:41:31 +0400
Subject: [PATCH] Fix a bug with concurrent invocation of session triggers.
A session trigger would always use the same coroutine, for both connect and
disconnect, as well as for multiple sessions.
If a trigger runs insert() or update(), anything that yields the current
coro, the coro stack would get corrupted for the next parallel invocation.
Use an own coroutine for each invocation of a session trigger.
---
src/lua/session.m | 56 +++++++++++++++++++----------------------------
1 file changed, 23 insertions(+), 33 deletions(-)
diff --git a/src/lua/session.m b/src/lua/session.m
index 523d8d7c07..23bc997d93 100644
--- a/src/lua/session.m
+++ b/src/lua/session.m
@@ -91,7 +91,7 @@ lbox_session_peer(struct lua_State *L)
struct lbox_session_trigger
{
struct session_trigger *trigger;
- int coro_ref;
+ int ref;
};
static struct lbox_session_trigger on_connect =
@@ -104,26 +104,21 @@ lbox_session_run_trigger(void *param)
{
struct lbox_session_trigger *trigger = param;
/* Copy the referenced callable object object stack. */
- lua_rawgeti(tarantool_L, LUA_REGISTRYINDEX, trigger->coro_ref);
+ lua_State *L = lua_newthread(tarantool_L);
+ int coro_ref = luaL_ref(tarantool_L, LUA_REGISTRYINDEX);
+ lua_rawgeti(tarantool_L, LUA_REGISTRYINDEX, trigger->ref);
+ /** Move the function to be called to the new coro. */
+ lua_xmove(tarantool_L, L, 1);
- struct lua_State *coro_L = lua_tothread(tarantool_L, -1);
- lua_pop(tarantool_L, 1);
- /*
- * If there was junk from previous invocation of the
- * trigger, clear it, only leaving on the stack the chunk
- * to be run. The stack may be polluted when previous
- * invocation ended up with an error.
- */
- lua_settop(coro_L, 1);
- /* lua_call pops the function, make a copy */
- lua_pushvalue(coro_L, -1);
@try {
- lua_call(coro_L, 0, 0);
+ lua_call(L, 0, 0);
} @catch (tnt_Exception *e) {
@throw;
} @catch (...) {
tnt_raise(ClientError, :ER_PROC_LUA,
- lua_tostring(coro_L, -1));
+ lua_tostring(L, -1));
+ } @finally {
+ luaL_unref(tarantool_L, LUA_REGISTRYINDEX, coro_ref);
}
}
@@ -137,36 +132,31 @@ lbox_session_set_trigger(struct lua_State *L,
luaL_error(L, "session.on_connect(chunk): bad arguments");
}
- struct lua_State *coro_L;
-
- if (trigger->coro_ref != LUA_NOREF) {
- lua_rawgeti(L, LUA_REGISTRYINDEX, trigger->coro_ref);
- coro_L = lua_tothread(L, -1);
- lua_pop(L, 1); /* pop the coro. */
- /* If there was junk from previous invocation, clear it. */
- lua_settop(coro_L, 1);
+ /* Pop the old trigger */
+ if (trigger->ref != LUA_NOREF) {
+ lua_rawgeti(L, LUA_REGISTRYINDEX, trigger->ref);
+ luaL_unref(L, LUA_REGISTRYINDEX, trigger->ref);
} else {
- coro_L = lua_newthread(L);
- /* Reference the new thread and pop it. */
- trigger->coro_ref = luaL_ref(L, LUA_REGISTRYINDEX);
- lua_pushnil(coro_L);
+ lua_pushnil(L);
}
- /** Move the chunk to the coroutine in will be run in. */
- lua_xmove(L, coro_L, 1);
- /* Return the old chunk. */
- lua_insert(coro_L, -2);
- lua_xmove(coro_L, L, 1);
+
/*
* Set or clear the trigger. Return the old value of the
* trigger.
*/
- if (lua_type(coro_L, -1) == LUA_TNIL) {
+ if (lua_type(L, -2) == LUA_TNIL) {
+ trigger->ref = LUA_NOREF;
trigger->trigger->trigger = NULL;
trigger->trigger->param = NULL;
} else {
+ /* Move the trigger to the top of the stack. */
+ lua_insert(L, -2);
+ /* Reference the new trigger. Pops it. */
+ trigger->ref = luaL_ref(L, LUA_REGISTRYINDEX);
trigger->trigger->trigger = lbox_session_run_trigger;
trigger->trigger->param = trigger;
}
+ /* Return the old trigger. */
return 1;
}
--
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