avoid overflow in integer multiplication

This changeset basically replaces `ruby_xmalloc(x * y)` into
`ruby_xmalloc2(x, y)`.  Some convenient functions are also
provided for instance `rb_xmalloc_mul_add(x, y, z)` which allocates
x * y + z byes.

1 files changed, 1 insertions, 1 deletions

diff --git a/vm_backtrace.c b/vm_backtrace.c
index 44a4ac0784..b04f6dac31 100644
--- a/vm_backtrace.c
+++ b/vm_backtrace.c
@@ -526,7 +526,7 @@ bt_init(void *ptr, size_t size)
     struct bt_iter_arg *arg = (struct bt_iter_arg *)ptr;
     arg->btobj = backtrace_alloc(rb_cBacktrace);
     GetCoreDataFromValue(arg->btobj, rb_backtrace_t, arg->bt);
-    arg->bt->backtrace_base = arg->bt->backtrace = ruby_xmalloc(sizeof(rb_backtrace_location_t) * size);
+    arg->bt->backtrace_base = arg->bt->backtrace = ALLOC_N(rb_backtrace_location_t, size);
     arg->bt->backtrace_size = 0;
 }