'lua_checkstack' doesn't need to check stack overflow
'luaD_growstack' already checks that. This commit also fixes an
internal bug in 'luaD_growstack': a large 'n' could cause an arithmetic
overflow when computing 'needed'.
diff --git a/all b/all
index 039f609..86f38ac 100755
--- a/all
+++ b/all
@@ -1,7 +1,7 @@
make -s -j
cd testes/libs; make -s
cd .. # back to directory 'testes'
-ulimit -S -s 1000
+ulimit -S -s 1100
if { ../lua -W all.lua; } then
echo -e "\n\n final OK!!!!\n\n"
else
diff --git a/lapi.c b/lapi.c
index 5ee6579..352a385 100644
--- a/lapi.c
+++ b/lapi.c
@@ -114,13 +114,8 @@
api_check(L, n >= 0, "negative 'n'");
if (L->stack_last - L->top > n) /* stack large enough? */
res = 1; /* yes; check is OK */
- else { /* no; need to grow stack */
- int inuse = cast_int(L->top - L->stack) + EXTRA_STACK;
- if (inuse > LUAI_MAXSTACK - n) /* can grow without overflow? */
- res = 0; /* no */
- else /* try to grow stack */
- res = luaD_growstack(L, n, 0);
- }
+ else /* need to grow stack */
+ res = luaD_growstack(L, n, 0);
if (res && ci->top < L->top + n)
ci->top = L->top + n; /* adjust frame top */
lua_unlock(L);
diff --git a/ldo.c b/ldo.c
index 8e4faf0..5aa6d59 100644
--- a/ldo.c
+++ b/ldo.c
@@ -227,7 +227,7 @@
luaD_throw(L, LUA_ERRERR); /* error inside message handler */
return 0; /* if not 'raiseerror', just signal it */
}
- else {
+ else if (n < LUAI_MAXSTACK) { /* avoids arithmetic overflows */
int newsize = 2 * size; /* tentative new size */
int needed = cast_int(L->top - L->stack) + n;
if (newsize > LUAI_MAXSTACK) /* cannot cross the limit */
@@ -236,14 +236,13 @@
newsize = needed;
if (l_likely(newsize <= LUAI_MAXSTACK))
return luaD_reallocstack(L, newsize, raiseerror);
- else { /* stack overflow */
- /* add extra size to be able to handle the error message */
- luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror);
- if (raiseerror)
- luaG_runerror(L, "stack overflow");
- return 0;
- }
}
+ /* else stack overflow */
+ /* add extra size to be able to handle the error message */
+ luaD_reallocstack(L, ERRORSTACKSIZE, raiseerror);
+ if (raiseerror)
+ luaG_runerror(L, "stack overflow");
+ return 0;
}
diff --git a/luaconf.h b/luaconf.h
index d42d14b..fcc0018 100644
--- a/luaconf.h
+++ b/luaconf.h
@@ -728,7 +728,7 @@
** CHANGE it if you need a different limit. This limit is arbitrary;
** its only purpose is to stop Lua from consuming unlimited stack
** space (and to reserve some numbers for pseudo-indices).
-** (It must fit into max(size_t)/32.)
+** (It must fit into max(size_t)/32 and max(int)/2.)
*/
#if LUAI_IS32INT
#define LUAI_MAXSTACK 1000000
diff --git a/testes/coroutine.lua b/testes/coroutine.lua
index 76c9d6e..15fccc3 100644
--- a/testes/coroutine.lua
+++ b/testes/coroutine.lua
@@ -741,20 +741,17 @@
if not _soft then
-- bug (stack overflow)
- local j = 2^9
- local lim = 1000000 -- (C stack limit; assume 32-bit machine)
- local t = {lim - 10, lim - 5, lim - 1, lim, lim + 1}
+ local lim = 1000000 -- stack limit; assume 32-bit machine
+ local t = {lim - 10, lim - 5, lim - 1, lim, lim + 1, lim + 5}
for i = 1, #t do
local j = t[i]
- co = coroutine.create(function()
- local t = {}
- for i = 1, j do t[i] = i end
- return table.unpack(t)
+ local co = coroutine.create(function()
+ return table.unpack({}, 1, j)
end)
local r, msg = coroutine.resume(co)
- assert(not r)
+ -- must fail for unpacking larger than stack limit
+ assert(j < lim or not r)
end
- co = nil
end
