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Merge pull request #567 from beoran/beoran_stack_overflow_fix

Keep stack depth and allocation better under control and fix crash on infinite recursion.
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matz committed Dec 5, 2012
2 parents 222bd97 + 039679f commit 40daee12cfbf6dac4421f47c9c953788985fe238
Showing with 52 additions and 6 deletions.
  1. +29 −6 src/vm.c
  2. +23 −0 test/t/exception.rb
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@@ -38,6 +38,19 @@
#define STACK_INIT_SIZE 128
#define CALLINFO_INIT_SIZE 32
/* Define amount of linear stack growth. */
#ifndef MRB_STACK_GROWTH
#define MRB_STACK_GROWTH 128
#endif
/* Maximum stack depth. Should be set lower on memory constrained systems.
The value below allows about 60000 recursive calls in the simplest case. */
#ifndef MRB_STACK_MAX
#define MRB_STACK_MAX ((1<<18) - MRB_STACK_GROWTH)
#endif
static inline void
stack_copy(mrb_value *dst, const mrb_value *src, size_t size)
{
@@ -52,7 +65,7 @@ static void
stack_init(mrb_state *mrb)
{
/* assert(mrb->stack == NULL); */
mrb->stbase = (mrb_value *)mrb_calloc(mrb, STACK_INIT_SIZE, sizeof(mrb_value));
mrb->stbase = (mrb_value *)mrb_calloc(mrb, STACK_INIT_SIZE, sizeof(mrb_value));
mrb->stend = mrb->stbase + STACK_INIT_SIZE;
mrb->stack = mrb->stbase;
@@ -79,29 +92,39 @@ envadjust(mrb_state *mrb, mrb_value *oldbase, mrb_value *newbase)
}
}
/** def rec ; $deep =+ 1 ; if $deep > 1000 ; return 0 ; end ; rec ; end */
static void
stack_extend(mrb_state *mrb, int room, int keep)
{
int size, off;
if (mrb->stack + room >= mrb->stend) {
mrb_value *oldbase = mrb->stbase;
size = mrb->stend - mrb->stbase;
off = mrb->stack - mrb->stbase;
if (room <= size) /* double size is enough? */
size *= 2;
/* Use linear stack growth.
It is slightly slower than doubling thestack space,
but it saves memory on small devices. */
if (room <= size)
size += MRB_STACK_GROWTH;
else
size += room;
mrb->stbase = (mrb_value *)mrb_realloc(mrb, mrb->stbase, sizeof(mrb_value) * size);
mrb->stack = mrb->stbase + off;
mrb->stend = mrb->stbase + size;
envadjust(mrb, oldbase, mrb->stbase);
/* Raise an exception if the new stack size will be too large,
to prevent infinite recursion. However, do this only after resizing the stack, so mrb_raisef has stack space to work with. */
if(size > MRB_STACK_MAX) {
mrb_raisef(mrb, E_RUNTIME_ERROR, "stack level too deep. (limit=%d)", MRB_STACK_MAX);
}
}
if (room > keep) {
int i;
for (i=keep; i<room; i++) {
#ifndef MRB_NAN_BOXING
static const mrb_value mrb_value_zero = { { 0 } };
View
@@ -290,3 +290,26 @@ def exception_test14
assert('Exception#inspect without message') do
Exception.new.inspect
end
# very deeply recursive function that stil returns albeit very deeply so
$test_infinite_recursion = 0
TEST_INFINITE_RECURSION_MAX = 100000
def test_infinite_recursion
$test_infinite_recursion += 1
if $test_infinite_recursion > TEST_INFINITE_RECURSION_MAX
return $test_infinite_recursion
end
test_infinite_recursion
end
assert('Infinite recursion should result in an exception being raised') do
a = begin
test_infinite_recursion
rescue
:ok
end
# OK if an exception was caught, otherwise a number will be stored in a
a == :ok
end

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