diff --git a/io.c b/io.c
index 3e184f2..66e399b 100644
--- a/io.c
+++ b/io.c
@@ -374,6 +374,8 @@ rb_cloexec_fcntl_dupfd(int fd, int minfd)
 #  endif
 #endif
 
+#define rb_sys_fail_path(path) rb_sys_fail(NIL_P(path) ? 0 : RSTRING_PTR(path))
+
 static int io_fflush(rb_io_t *);
 
 #define NEED_NEWLINE_DECORATOR_ON_READ(fptr) ((fptr)->mode & FMODE_TEXTMODE)
@@ -423,6 +425,7 @@ inline static int set_binary_mode_with_seek_cur(rb_io_t *fptr) {
     ssize_t read_size;
     long i;
     long newlines = 0;
+    long extra_max;
     char *p;
 
     if (!rb_w32_fd_is_text((fptr)->fd)) return O_BINARY;
@@ -443,23 +446,31 @@ inline static int set_binary_mode_with_seek_cur(rb_io_t *fptr) {
 	setmode((fptr)->fd, O_BINARY);
 	return O_TEXT;
     }
-    /* add extra offset for '\r' */
-    p = (fptr)->rbuf.ptr+(fptr)->rbuf.off;
+    /* add extra offset for removed '\r' in rbuf */
+    extra_max = pos - (fptr)->rbuf.len;
+    p = (fptr)->rbuf.ptr + (fptr)->rbuf.off;
     for (i = 0; i < (fptr)->rbuf.len; i++) {
 	if (*p == '\n') newlines++;
+	if (extra_max == newlines) break;
 	p++;
     }
     while (newlines >= 0) {
 	r = lseek((fptr)->fd, pos - (fptr)->rbuf.len - newlines, SEEK_SET);
 	if (newlines == 0) break;
-	if (read_size = _read((fptr)->fd, (fptr)->rbuf.ptr, (fptr)->rbuf.len + newlines)) {
-	    if (read_size == (fptr)->rbuf.len) {
-		lseek((fptr)->fd, r, SEEK_SET);
-		break;
-	    }
-	    else {
-		newlines--;
-	    }
+	if (r < 0) {
+	    newlines--;
+	    continue;
+	}
+	read_size = _read((fptr)->fd, (fptr)->rbuf.ptr, (fptr)->rbuf.len + newlines);
+	if (read_size < 0) {
+	    rb_sys_fail_path(fptr->pathv);
+	}
+	if (read_size == (fptr)->rbuf.len) {
+	    lseek((fptr)->fd, r, SEEK_SET);
+	    break;
+	}
+	else {
+	    newlines--;
 	}
     }
     (fptr)->rbuf.off = 0;
@@ -484,8 +495,6 @@ inline static int set_binary_mode_with_seek_cur(rb_io_t *fptr) {
 #define shutdown(a,b)	0
 #endif
 
-#define rb_sys_fail_path(path) rb_sys_fail(NIL_P(path) ? 0 : RSTRING_PTR(path))
-
 #if defined(_WIN32)
 #define is_socket(fd, path)	rb_w32_is_socket(fd)
 #elif !defined(S_ISSOCK)
diff --git a/test/ruby/test_io_m17n.rb b/test/ruby/test_io_m17n.rb
index 9adf7c8..b7460bf 100644
--- a/test/ruby/test_io_m17n.rb
+++ b/test/ruby/test_io_m17n.rb
@@ -2314,4 +2314,15 @@ EOT
       end
     }
   end if /mswin|mingw/ =~ RUBY_PLATFORM
+
+  def test_seek_with_setting_binmode
+    with_tmpdir {
+      str = "a\r\nb\r\nc\r\n\r\n\n\n\n\n\n\n\n"
+      generate_file("tmp", str)
+      open("tmp", "r") do |f|
+        assert_equal("a\n", f.gets)      # text
+        assert_equal("b\r\n", f.read(3)) # binary
+      end
+    }
+  end if /mswin|mingw/ =~ RUBY_PLATFORM
 end