util.c: bump stack size in ruby_qsort()

* util.c (ruby_qsort): fix potential stack overflow on a large
  machine.  based on the patch by Conrad Irwin <conrad.irwin AT
  gmail.com> at [ruby-core:51816].  [Bug #7772]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44195 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 1 deletions

diff --git a/util.c b/util.c
index f6f233b6e4..b0f9030c42 100644
--- a/util.c
+++ b/util.c
@@ -310,7 +310,9 @@ ruby_qsort(void* base, const size_t nel, const size_t size, cmpfunc_t *cmp, void
   char *L = base;                    	/* left end of current region */
   char *R = (char*)base + size*(nel-1); /* right end of current region */
   size_t chklim = 63;                   /* threshold of ordering element check */
-  stack_node stack[32], *top = stack;   /* 32 is enough for 32bit CPU */
+  enum {size_bits = sizeof(size) * CHAR_BIT};
+  stack_node stack[size_bits];          /* enough for size_t size */
+  stack_node *top = stack;
   int mmkind;
   size_t high, low, n;