1 files changed, 8 insertions, 2 deletions
diff --git a/fs/file.c b/fs/file.c
index 3d2eb4c..6c672ad 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -664,11 +664,17 @@ static struct file *__fget(unsigned int fd, fmode_t mask)
 	struct file *file;
 
 	rcu_read_lock();
+loop:
 	file = fcheck_files(files, fd);
 	if (file) {
-		/* File object ref couldn't be taken */
-		if ((file->f_mode & mask) || !get_file_rcu(file))
+		/* File object ref couldn't be taken.
+		 * dup2() atomicity guarantee is the reason
+		 * we loop to catch the new file (or NULL pointer)
+		 */
+		if (file->f_mode & mask)
 			file = NULL;
+		else if (!get_file_rcu(file))
+			goto loop;
 	}
 	rcu_read_unlock();