On Wed, Dec 09, 2020 at 12:04:38PM -0600, Eric W. Biederman wrote:
> @@ -397,8 +397,9 @@ static struct fdtable *close_files(struct files_struct *
> files)
> set = fdt->open_fds[j++];
> while (set) {
> if (set & 1) {
> - struct file * file = xchg(&fdt->fd[i], NULL);
> + struct file * file = fdt->fd[i];
> if (file) {
> + rcu_assign_pointer(fdt->fd[i], NULL);
Assuming this is safe, you can use RCU_INIT_POINTER() here because you're
storing NULL, so you don't need the wmb() before storing the pointer.
