int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
{
	transaction_t *transaction = handle->h_transaction;
	journal_t *journal = transaction->t_journal;
	tid_t		tid;
	int		need_to_start, ret;

	/* If we've had an abort of any type, don't even think about
	 * actually doing the restart! */
	if (is_handle_aborted(handle))
		return 0;

	/*
	 * First unlink the handle from its current transaction, and start the
	 * commit on that.
	 */
	J_ASSERT(atomic_read(&transaction->t_updates) > 0);
	J_ASSERT(journal_current_handle() == handle);

	read_lock(&journal->j_state_lock);
	spin_lock(&transaction->t_handle_lock);
	atomic_sub(handle->h_buffer_credits,
		   &transaction->t_outstanding_credits);
	if (atomic_dec_and_test(&transaction->t_updates))
		wake_up(&journal->j_wait_updates);
	spin_unlock(&transaction->t_handle_lock);

	jbd_debug(2, "restarting handle %p\n", handle);
	tid = transaction->t_tid;
	need_to_start = !tid_geq(journal->j_commit_request, tid);
	read_unlock(&journal->j_state_lock);
	if (need_to_start)
		jbd2_log_start_commit(journal, tid);

	lock_map_release(&handle->h_lockdep_map);
	handle->h_buffer_credits = nblocks;
	ret = start_this_handle(journal, handle, gfp_mask);
	return ret;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.