SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
		  const u64 persistent_fid, const u64 volatile_fid,
		  __u8 oplock_level)
{
	struct smb_rqst rqst;
	int rc;
	struct smb2_oplock_break *req = NULL;
	struct cifs_ses *ses = tcon->ses;
	int flags = CIFS_OBREAK_OP;
	unsigned int total_len;
	struct kvec iov[1];
	struct kvec rsp_iov;
	int resp_buf_type;

	cifs_dbg(FYI, "SMB2_oplock_break\n");
	rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, (void **) &req,
			     &total_len);
	if (rc)
		return rc;

	if (smb3_encryption_required(tcon))
		flags |= CIFS_TRANSFORM_REQ;

	req->VolatileFid = volatile_fid;
	req->PersistentFid = persistent_fid;
	req->OplockLevel = oplock_level;
	req->sync_hdr.CreditRequest = cpu_to_le16(1);

	flags |= CIFS_NO_RESP;

	iov[0].iov_base = (char *)req;
	iov[0].iov_len = total_len;

	memset(&rqst, 0, sizeof(struct smb_rqst));
	rqst.rq_iov = iov;
	rqst.rq_nvec = 1;

	rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
	cifs_small_buf_release(req);

	if (rc) {
		cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE);
		cifs_dbg(FYI, "Send error in Oplock Break = %d\n", rc);
	}

	return rc;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.