CIFSSMBWrite2(const int xid, struct cifs_io_parms *io_parms,
	      unsigned int *nbytes, struct kvec *iov, int n_vec,
	      const int long_op)
{
	int rc = -EACCES;
	WRITE_REQ *pSMB = NULL;
	int wct;
	int smb_hdr_len;
	int resp_buf_type = 0;
	__u32 pid = io_parms->pid;
	__u16 netfid = io_parms->netfid;
	__u64 offset = io_parms->offset;
	struct cifs_tcon *tcon = io_parms->tcon;
	unsigned int count = io_parms->length;

	*nbytes = 0;

	cFYI(1, "write2 at %lld %d bytes", (long long)offset, count);

	if (tcon->ses->capabilities & CAP_LARGE_FILES) {
		wct = 14;
	} else {
		wct = 12;
		if ((offset >> 32) > 0) {
			/* can not handle big offset for old srv */
			return -EIO;
		}
	}
	rc = small_smb_init(SMB_COM_WRITE_ANDX, wct, tcon, (void **) &pSMB);
	if (rc)
		return rc;

	pSMB->hdr.Pid = cpu_to_le16((__u16)pid);
	pSMB->hdr.PidHigh = cpu_to_le16((__u16)(pid >> 16));

	/* tcon and ses pointer are checked in smb_init */
	if (tcon->ses->server == NULL)
		return -ECONNABORTED;

	pSMB->AndXCommand = 0xFF;	/* none */
	pSMB->Fid = netfid;
	pSMB->OffsetLow = cpu_to_le32(offset & 0xFFFFFFFF);
	if (wct == 14)
		pSMB->OffsetHigh = cpu_to_le32(offset >> 32);
	pSMB->Reserved = 0xFFFFFFFF;
	pSMB->WriteMode = 0;
	pSMB->Remaining = 0;

	pSMB->DataOffset =
	    cpu_to_le16(offsetof(struct smb_com_write_req, Data) - 4);

	pSMB->DataLengthLow = cpu_to_le16(count & 0xFFFF);
	pSMB->DataLengthHigh = cpu_to_le16(count >> 16);
	/* header + 1 byte pad */
	smb_hdr_len = be32_to_cpu(pSMB->hdr.smb_buf_length) + 1;
	if (wct == 14)
		inc_rfc1001_len(pSMB, count + 1);
	else /* wct == 12 */
		inc_rfc1001_len(pSMB, count + 5); /* smb data starts later */
	if (wct == 14)
		pSMB->ByteCount = cpu_to_le16(count + 1);
	else /* wct == 12 */ /* bigger pad, smaller smb hdr, keep offset ok */ {
		struct smb_com_writex_req *pSMBW =
				(struct smb_com_writex_req *)pSMB;
		pSMBW->ByteCount = cpu_to_le16(count + 5);
	}
	iov[0].iov_base = pSMB;
	if (wct == 14)
		iov[0].iov_len = smb_hdr_len + 4;
	else /* wct == 12 pad bigger by four bytes */
		iov[0].iov_len = smb_hdr_len + 8;


	rc = SendReceive2(xid, tcon->ses, iov, n_vec + 1, &resp_buf_type,
			  long_op);
	cifs_stats_inc(&tcon->num_writes);
	if (rc) {
		cFYI(1, "Send error Write2 = %d", rc);
	} else if (resp_buf_type == 0) {
		/* presumably this can not happen, but best to be safe */
		rc = -EIO;
	} else {
		WRITE_RSP *pSMBr = (WRITE_RSP *)iov[0].iov_base;
		*nbytes = le16_to_cpu(pSMBr->CountHigh);
		*nbytes = (*nbytes) << 16;
		*nbytes += le16_to_cpu(pSMBr->Count);

		/*
		 * Mask off high 16 bits when bytes written as returned by the
		 * server is greater than bytes requested by the client. OS/2
		 * servers are known to set incorrect CountHigh values.
		 */
		if (*nbytes > count)
			*nbytes &= 0xFFFF;
	}

/*	cifs_small_buf_release(pSMB); */ /* Freed earlier now in SendReceive2 */
	if (resp_buf_type == CIFS_SMALL_BUFFER)
		cifs_small_buf_release(iov[0].iov_base);
	else if (resp_buf_type == CIFS_LARGE_BUFFER)
		cifs_buf_release(iov[0].iov_base);

	/* Note: On -EAGAIN error only caller can retry on handle based calls
		since file handle passed in no longer valid */

	return rc;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.