There was a silly bug in the initial implementation where a loop
variable was not incremented. This commit increments the loop variable.

This bug is somewhat tricky to catch because it can only happen on loops
of two or more. If it is hit, it locks up a kernel thread in an infinite
loop.

Signed-off-by: Nikhil Jha <njha@janestreet.com>
Tested-by: Nikhil Jha <njha@janestreet.com>
Fixes: 08d6ee6d8a10 ("sunrpc: implement rfc2203 rpcsec_gss seqnum cache")
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

Pull nfsd fixes from Chuck Lever:

 - Two fixes for commits in the nfsd-6.16 merge

 - One fix for the recently-added NFSD netlink facility

 - One fix for a remote SunRPC crasher

* tag 'nfsd-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  sunrpc: handle SVC_GARBAGE during svc auth processing as auth error
  nfsd: use threads array as-is in netlink interface
  SUNRPC: Cleanup/fix initial rq_pages allocation
  NFSD: Avoid corruption of a referring call list

tianshuo han reported a remotely-triggerable crash if the client sends a
kernel RPC server a specially crafted packet. If decoding the RPC reply
fails in such a way that SVC_GARBAGE is returned without setting the
rq_accept_statp pointer, then that pointer can be dereferenced and a
value stored there.

If it's the first time the thread has processed an RPC, then that
pointer will be set to NULL and the kernel will crash. In other cases,
it could create a memory scribble.

The server sunrpc code treats a SVC_GARBAGE return from svc_authenticate
or pg_authenticate as if it should send a GARBAGE_ARGS reply. RFC 5531
says that if authentication fails that the RPC should be rejected
instead with a status of AUTH_ERR.

Handle a SVC_GARBAGE return as an AUTH_ERROR, with a reason of
AUTH_BADCRED instead of returning GARBAGE_ARGS in that case. This
sidesteps the whole problem of touching the rpc_accept_statp pointer in
this situation and avoids the crash.

Cc: stable@kernel.org
Fixes: 29cd2927fb91 ("SUNRPC: Fix encoding of accepted but unsuccessful RPC replies")
Reported-by: tianshuo han <hantianshuo233@gmail.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

While investigating some reports of memory-constrained NUMA machines
failing to mount v3 and v4.0 nfs mounts, we found that svc_init_buffer()
was not attempting to retry allocations from the bulk page allocator.
Typically, this results in a single page allocation being returned and
the mount attempt fails with -ENOMEM.  A retry would have allowed the mount
to succeed.

Additionally, it seems that the bulk allocation in svc_init_buffer() is
redundant because svc_alloc_arg() will perform the required allocation and
does the correct thing to retry the allocations.

The call to allocate memory in svc_alloc_arg() drops the preferred node
argument, but I expect we'll still allocate on the preferred node because
the allocation call happens within the svc thread context, which chooses
the node with memory closest to the current thread's execution.

This patch cleans out the bulk allocation in svc_init_buffer() to allow
svc_alloc_arg() to handle the allocation/retry logic for rq_pages.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Fixes: ed603bcf4fea ("sunrpc: Replace the rq_pages array with dynamically-allocated memory")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Move this API to the canonical timer_*() namespace.

[ tglx: Redone against pre rc1 ]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com

Pull NFS clent updates from Anna Schumaker:
 "New Features:

   - Implement the Sunrpc rfc2203 rpcsec_gss sequence number cache

   - Add support for FALLOC_FL_ZERO_RANGE on NFS v4.2

   - Add a localio sysfs attribute

  Stable Fixes:

   - Fix double-unlock bug in nfs_return_empty_folio()

   - Don't check for OPEN feature support in v4.1

   - Always probe for LOCALIO support asynchronously

   - Prevent hang on NFS mounts with xprtsec=[m]tls

  Other Bugfixes:

   - xattr handlers should check for absent nfs filehandles

   - Fix setattr caching of TIME_[MODIFY|ACCESS]_SET when timestamps are
     delegated

   - Fix listxattr to return selinux security labels

   - Connect to NFSv3 DS using TLS if MDS connection uses TLS

   - Clear SB_RDONLY before getting a superblock, and ignore when
     remounting

   - Fix incorrect handling of NFS error codes in nfs4_do_mkdir()

   - Various nfs_localio fixes from Neil Brown that include fixing an
     rcu compilation error found by older gcc versions.

   - Update stats on flexfiles pNFS DSes when receiving NFS4ERR_DELAY

  Cleanups:

   - Add a refcount tracker for struct net in the nfs_client

   - Allow FREE_STATEID to clean up delegations

   - Always set NLINK even if the server doesn't support it

   - Cleanups to the NFS folio writeback code

   - Remove dead code from xs_tcp_tls_setup_socket()"

* tag 'nfs-for-6.16-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (30 commits)
  flexfiles/pNFS: update stats on NFS4ERR_DELAY for v4.1 DSes
  nfs_localio: change nfsd_file_put_local() to take a pointer to __rcu pointer
  nfs_localio: protect race between nfs_uuid_put() and nfs_close_local_fh()
  nfs_localio: duplicate nfs_close_local_fh()
  nfs_localio: simplify interface to nfsd for getting nfsd_file
  nfs_localio: always hold nfsd net ref with nfsd_file ref
  nfs_localio: use cmpxchg() to install new nfs_file_localio
  SUNRPC: Remove dead code from xs_tcp_tls_setup_socket()
  SUNRPC: Prevent hang on NFS mount with xprtsec=[m]tls
  nfs: fix incorrect handling of large-number NFS errors in nfs4_do_mkdir()
  nfs: ignore SB_RDONLY when remounting nfs
  nfs: clear SB_RDONLY before getting superblock
  NFS: always probe for LOCALIO support asynchronously
  pnfs/flexfiles: connect to NFSv3 DS using TLS if MDS connection uses TLS
  NFS: add localio to sysfs
  nfs: use writeback_iter directly
  nfs: refactor nfs_do_writepage
  nfs: don't return AOP_WRITEPAGE_ACTIVATE from nfs_do_writepage
  nfs: fold nfs_page_async_flush into nfs_do_writepage
  NFSv4: Always set NLINK even if the server doesn't support it
  ...

xs_tcp_tls_finish_connecting() already marks the upper xprt
connected, so the same code in xs_tcp_tls_setup_socket() is
never executed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

Engineers at Hammerspace noticed that sometimes mounting with
"xprtsec=tls" hangs for a minute or so, and then times out, even
when the NFS server is reachable and responsive.

kTLS shuts off data_ready callbacks if strp->msg_ready is set to
mitigate data_ready callbacks when a full TLS record is not yet
ready to be read from the socket.

Normally msg_ready is clear when the first TLS record arrives on
a socket. However, I observed that sometimes tls_setsockopt() sets
strp->msg_ready, and that prevents forward progress because
tls_data_ready() becomes a no-op.

Moreover, Jakub says: "If there's a full record queued at the time
when [tlshd] passes the socket back to the kernel, it's up to the
reader to read the already queued data out." So SunRPC cannot
expect a data_ready call when ingress data is already waiting.

Add an explicit poll after SunRPC's upper transport is set up to
pick up any data that arrived after the TLS handshake but before
transport set-up is complete.

Reported-by: Steve Sears <sjs@hammerspace.com>
Suggested-by: Jakub Kacinski <kuba@kernel.org>
Fixes: 75eb6af7acdf ("SUNRPC: Add a TCP-with-TLS RPC transport class")
Tested-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

Pull nfsd updates from Chuck Lever:
 "The marquee feature for this release is that the limit on the maximum
  rsize and wsize has been raised to 4MB. The default remains at 1MB,
  but risk-seeking administrators now have the ability to try larger I/O
  sizes with NFS clients that support them. Eventually the default
  setting will be increased when we have confidence that this change
  will not have negative impact.

  With v6.16, NFSD now has its own debugfs file system where we can add
  experimental features and make them available outside of our
  development community without impacting production deployments. The
  first experimental setting added is one that makes all NFS READ
  operations use vfs_iter_read() instead of the NFSD splice actor. The
  plan is to eventually retire the splice actor, as that will enable a
  number of new capabilities such as the use of struct bio_vec from the
  top to the bottom of the NFSD stack.

  Jeff Layton contributed a number of observability improvements. The
  use of dprintk() in a number of high-traffic code paths has been
  replaced with static trace points.

  This release sees the continuation of efforts to harden the NFSv4.2
  COPY operation. Soon, the restriction on async COPY operations can be
  lifted.

  Many thanks to the contributors, reviewers, testers, and bug reporters
  who participated during the v6.16 development cycle"

* tag 'nfsd-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (60 commits)
  xdrgen: Fix code generated for counted arrays
  SUNRPC: Bump the maximum payload size for the server
  NFSD: Add a "default" block size
  NFSD: Remove NFSSVC_MAXBLKSIZE_V2 macro
  NFSD: Remove NFSD_BUFSIZE
  sunrpc: Remove the RPCSVC_MAXPAGES macro
  svcrdma: Adjust the number of entries in svc_rdma_send_ctxt::sc_pages
  svcrdma: Adjust the number of entries in svc_rdma_recv_ctxt::rc_pages
  sunrpc: Adjust size of socket's receive page array dynamically
  SUNRPC: Remove svc_rqst :: rq_vec
  SUNRPC: Remove svc_fill_write_vector()
  NFSD: Use rqstp->rq_bvec in nfsd_iter_write()
  SUNRPC: Export xdr_buf_to_bvec()
  NFSD: De-duplicate the svc_fill_write_vector() call sites
  NFSD: Use rqstp->rq_bvec in nfsd_iter_read()
  sunrpc: Replace the rq_bvec array with dynamically-allocated memory
  sunrpc: Replace the rq_pages array with dynamically-allocated memory
  sunrpc: Remove backchannel check in svc_init_buffer()
  sunrpc: Add a helper to derive maxpages from sv_max_mesg
  svcrdma: Reduce the number of rdma_rw contexts per-QP
  ...

Pull vfs directory lookup updates from Christian Brauner:
 "This contains cleanups for the lookup_one*() family of helpers.

  We expose a set of functions with names containing "lookup_one_len"
  and others without the "_len". This difference has nothing to do with
  "len". It's rater a historical accident that can be confusing.

  The functions without "_len" take a "mnt_idmap" pointer. This is found
  in the "vfsmount" and that is an important question when choosing
  which to use: do you have a vfsmount, or are you "inside" the
  filesystem. A related question is "is permission checking relevant
  here?".

  nfsd and cachefiles *do* have a vfsmount but *don't* use the non-_len
  functions. They pass nop_mnt_idmap and refuse to work on filesystems
  which have any other idmap.

  This work changes nfsd and cachefile to use the lookup_one family of
  functions and to explictily pass &nop_mnt_idmap which is consistent
  with all other vfs interfaces used where &nop_mnt_idmap is explicitly
  passed.

  The remaining uses of the "_one" functions do not require permission
  checks so these are renamed to be "_noperm" and the permission
  checking is removed.

  This series also changes these lookup function to take a qstr instead
  of separate name and len. In many cases this simplifies the call"

* tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  VFS: change lookup_one_common and lookup_noperm_common to take a qstr
  Use try_lookup_noperm() instead of d_hash_and_lookup() outside of VFS
  VFS: rename lookup_one_len family to lookup_noperm and remove permission check
  cachefiles: Use lookup_one() rather than lookup_one_len()
  nfsd: Use lookup_one() rather than lookup_one_len()
  VFS: improve interface for lookup_one functions