Code: nfs3svc_decode_readargs(struct svc_rqst *rqstp, __be32 *p,
					struct nfsd3_readargs *args)
{
	unsigned int len;
	int v;
	u32 max_blocksize = svc_max_payload(rqstp);

	p = decode_fh(p, &args->fh);
 	if (!p)
 		return 0;
 	p = xdr_decode_hyper(p, &args->offset);
 	args->count = ntohl(*p++);
 	len = min(args->count, max_blocksize);
 
 	/* set up the kvec */
	v=0;
	while (len > 0) {
		struct page *p = *(rqstp->rq_next_page++);

		rqstp->rq_vec[v].iov_base = page_address(p);
		rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
		len -= rqstp->rq_vec[v].iov_len;
 		v++;
 	}
 	args->vlen = v;
	return xdr_argsize_check(rqstp, p);
 }

Vulnerability Type: DoS 
CWE ID: CWE-404
Summary: The NFSv4 implementation in the Linux kernel through 4.11.1 allows local users to cause a denial of service (resource consumption) by leveraging improper channel callback shutdown when unmounting an NFSv4 filesystem, aka a *module reference and kernel daemon* leak.
Commit Message: Merge tag 'nfsd-4.12' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:
 "Another RDMA update from Chuck Lever, and a bunch of miscellaneous
  bugfixes"

* tag 'nfsd-4.12' of git://linux-nfs.org/~bfields/linux: (26 commits)
  nfsd: Fix up the "supattr_exclcreat" attributes
  nfsd: encoders mustn't use unitialized values in error cases
  nfsd: fix undefined behavior in nfsd4_layout_verify
  lockd: fix lockd shutdown race
  NFSv4: Fix callback server shutdown
  SUNRPC: Refactor svc_set_num_threads()
  NFSv4.x/callback: Create the callback service through svc_create_pooled
  lockd: remove redundant check on block
  svcrdma: Clean out old XDR encoders
  svcrdma: Remove the req_map cache
  svcrdma: Remove unused RDMA Write completion handler
  svcrdma: Reduce size of sge array in struct svc_rdma_op_ctxt
  svcrdma: Clean up RPC-over-RDMA backchannel reply processing
  svcrdma: Report Write/Reply chunk overruns
  svcrdma: Clean up RDMA_ERROR path
  svcrdma: Use rdma_rw API in RPC reply path
  svcrdma: Introduce local rdma_rw API helpers
  svcrdma: Clean up svc_rdma_get_inv_rkey()
  svcrdma: Add helper to save pages under I/O
  svcrdma: Eliminate RPCRDMA_SQ_DEPTH_MULT
  ...