(perl #130684) allocate enough space for the extra 'x'

77c8f26370dcc0e added support for a doubled x regexp flags, and ensured
the doubled flag was passed to the qr// created by
S_compile_runtime_code().

Unfortunately it didn't ensure enough space was allocated for that
extra 'x'.

1 files changed, 7 insertions, 1 deletions

diff --git a/t/re/pat.t b/t/re/pat.t
index d5e5d2fd4a..9abe5aa119 100644
--- a/t/re/pat.t
+++ b/t/re/pat.t
@@ -23,7 +23,7 @@ BEGIN {
     skip_all('no re module') unless defined &DynaLoader::boot_DynaLoader;
     skip_all_without_unicode_tables();
 
-plan tests => 835;  # Update this when adding/deleting tests.
+plan tests => 836;  # Update this when adding/deleting tests.
 
 run_tests() unless caller;
 
@@ -1901,6 +1901,12 @@ EOP
 	    }msx, { stderr => 1 }, "Offsets in debug output are not negative");
 	}
     }
+    {
+        # buffer overflow
+        fresh_perl_is("BEGIN{\$^H=0x200000}\ns/[(?{//xx",
+                      "Unmatched [ in regex; marked by <-- HERE in m/[ <-- HERE (?{/ at (eval 1) line 1.\n",
+                      {}, "buffer overflow for regexp component");
+    }
 } # End of sub run_tests
 
 1;