diff --git a/ldo.c b/ldo.c index c92573d6..8085b735 100644 --- a/ldo.c +++ b/ldo.c @@ -205,6 +205,25 @@ l_noret luaD_errerr (lua_State *L) { } +/* +** Check whether stacks have enough space to run a simple function (such +** as a finalizer): At least BASIC_STACK_SIZE in the Lua stack, two +** available CallInfos, and two "slots" in the C stack. +*/ +int luaD_checkminstack (lua_State *L) { + if (getCcalls(L) >= LUAI_MAXCCALLS - 2) + return 0; /* not enough C-stack slots */ + if (L->ci->next == NULL && luaE_extendCI(L, 0) == NULL) + return 0; /* unable to allocate first ci */ + if (L->ci->next->next == NULL && luaE_extendCI(L, 0) == NULL) + return 0; /* unable to allocate second ci */ + if (L->stack_last.p - L->top.p >= BASIC_STACK_SIZE) + return 1; /* enough (BASIC_STACK_SIZE) free slots in the Lua stack */ + else /* try to grow stack to a size with enough free slots */ + return luaD_growstack(L, BASIC_STACK_SIZE, 0); +} + + /* ** Reallocate the stack to a new size, correcting all pointers into it. ** In ISO C, any pointer use after the pointer has been deallocated is @@ -503,7 +522,7 @@ void luaD_poscall (lua_State *L, CallInfo *ci, int nres) { -#define next_ci(L) (L->ci->next ? L->ci->next : luaE_extendCI(L)) +#define next_ci(L) (L->ci->next ? L->ci->next : luaE_extendCI(L, 1)) l_sinline CallInfo *prepCallInfo (lua_State *L, StkId func, int nret, diff --git a/ldo.h b/ldo.h index 4de9540e..4c8db865 100644 --- a/ldo.h +++ b/ldo.h @@ -80,6 +80,7 @@ LUAI_FUNC int luaD_reallocstack (lua_State *L, int newsize, int raiseerror); LUAI_FUNC int luaD_growstack (lua_State *L, int n, int raiseerror); LUAI_FUNC void luaD_shrinkstack (lua_State *L); LUAI_FUNC void luaD_inctop (lua_State *L); +LUAI_FUNC int luaD_checkminstack (lua_State *L); LUAI_FUNC l_noret luaD_throw (lua_State *L, int errcode); LUAI_FUNC int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud); diff --git a/lgc.c b/lgc.c index c01660ab..52cea240 100644 --- a/lgc.c +++ b/lgc.c @@ -1242,7 +1242,7 @@ static void finishgencycle (lua_State *L, global_State *g) { correctgraylists(g); checkSizes(L, g); g->gcstate = GCSpropagate; /* skip restart */ - if (!g->gcemergency) + if (g->tobefnz != NULL && !g->gcemergency && luaD_checkminstack(L)) callallpendingfinalizers(L); } @@ -1632,11 +1632,12 @@ static lu_mem singlestep (lua_State *L) { break; } case GCScallfin: { /* call remaining finalizers */ - if (g->tobefnz && !g->gcemergency) { + if (g->tobefnz && !g->gcemergency && luaD_checkminstack(L)) { g->gcstopem = 0; /* ok collections during finalizers */ work = runafewfinalizers(L, GCFINMAX) * GCFINALIZECOST; } - else { /* emergency mode or no more finalizers */ + else { /* no more finalizers or emergency mode or no enough stack + to run finalizers */ g->gcstate = GCSpause; /* finish collection */ work = 0; } diff --git a/lstate.c b/lstate.c index f3f2ccfd..059be806 100644 --- a/lstate.c +++ b/lstate.c @@ -102,14 +102,19 @@ LUA_API int lua_setcstacklimit (lua_State *L, unsigned int limit) { } -CallInfo *luaE_extendCI (lua_State *L) { +CallInfo *luaE_extendCI (lua_State *L, int err) { CallInfo *ci; - lua_assert(L->ci->next == NULL); - ci = luaM_new(L, CallInfo); - lua_assert(L->ci->next == NULL); - L->ci->next = ci; + ci = luaM_reallocvector(L, NULL, 0, 1, CallInfo); + if (l_unlikely(ci == NULL)) { /* allocation failed? */ + if (err) + luaM_error(L); /* raise the error */ + return NULL; /* else only report it */ + } + ci->next = L->ci->next; ci->previous = L->ci; - ci->next = NULL; + L->ci->next = ci; + if (ci->next) + ci->next->previous = ci; ci->u.l.trap = 0; L->nci++; return ci; diff --git a/lstate.h b/lstate.h index 007704c8..97bb3e8f 100644 --- a/lstate.h +++ b/lstate.h @@ -395,7 +395,7 @@ union GCUnion { LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); -LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); +LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L, int err); LUAI_FUNC void luaE_shrinkCI (lua_State *L); LUAI_FUNC void luaE_checkcstack (lua_State *L); LUAI_FUNC void luaE_incCstack (lua_State *L);