1 files changed, 1 insertions, 1 deletions
diff --git a/string.c b/string.c
index 161c8a9894..5b60e9268b 100644
--- a/string.c
+++ b/string.c
@@ -2631,7 +2631,7 @@ rb_str_each_line(argc, argv, str)
 	    if (*++p != '\n') continue;
 	    while (*p == '\n') p++;
 	}
-	if (p[-1] == newline &&
+	if (RSTRING(str)->ptr < p && p[-1] == newline &&
 	    (rslen <= 1 ||
 	     rb_memcmp(RSTRING(rs)->ptr, p-rslen, rslen) == 0)) {
 	    line = rb_str_new5(str, s, p - s);