1 files changed, 1 insertions, 1 deletions
diff --git a/file.c b/file.c
index 00a2a0c7ee..b743a32fca 100644
--- a/file.c
+++ b/file.c
@@ -4058,7 +4058,7 @@ rb_file_flock(VALUE obj, VALUE operation)
     if (fptr->mode & FMODE_WRITABLE) {
 	rb_io_flush(obj);
     }
-    while ((int)rb_thread_blocking_region(rb_thread_flock, op, RUBY_UBF_IO, 0) < 0) {
+    while ((int)rb_thread_io_blocking_region(rb_thread_flock, op, fptr->fd) < 0) {
 	switch (errno) {
 	  case EAGAIN:
 	  case EACCES: