Pull execve fix from Eric Biederman:
 "While working on my exec cleanups I found a bug in exec that I
  introduced by accident a couple of years ago. I apparently missed the
  fact that bprm->file can change.

  Now I have a very personal motive to clean up exec and make it more
  approachable.

  The change is just moving woud_dump to where it acts on the final
  bprm->file not the initial bprm->file. I have been careful and tested
  and verify this fix works"

* 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  exec: Move would_dump into flush_old_exec

I goofed when I added mm->user_ns support to would_dump.  I missed the
fact that in the case of binfmt_loader, binfmt_em86, binfmt_misc, and
binfmt_script bprm->file is reassigned.  Which made the move of
would_dump from setup_new_exec to __do_execve_file before exec_binprm
incorrect as it can result in would_dump running on the script instead
of the interpreter of the script.

The net result is that the code stopped making unreadable interpreters
undumpable.  Which allows them to be ptraced and written to disk
without special permissions.  Oops.

The move was necessary because the call in set_new_exec was after
bprm->mm was no longer valid.

To correct this mistake move the misplaced would_dump from
__do_execve_file into flos_old_exec, before exec_mmap is called.

I tested and confirmed that without this fix I can attach with gdb to
a script with an unreadable interpreter, and with this fix I can not.

Cc: stable@vger.kernel.org
Fixes: f84df2a6f268 ("exec: Ensure mm->user_ns contains the execed files")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Pull cifs fixes from Steve French:
 "Three small cifs/smb3 fixes, one for stable"

* tag '5.7-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix leaked reference on requeued write
  cifs: Fix null pointer check in cifs_read
  CIFS: Spelling s/EACCESS/EACCES/

Pull io_uring fixes from Jens Axboe:
 "Two small fixes that should go into this release:

   - Check and handle zero length splice (Pavel)

   - Fix a regression in this merge window for fixed files used with
     polled block IO"

* tag 'io_uring-5.7-2020-05-15' of git://git.kernel.dk/linux-block:
  io_uring: polled fixed file must go through free iteration
  io_uring: fix zero len do_splice()

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable fixes:
   - nfs: fix NULL deference in nfs4_get_valid_delegation

  Bugfixes:
   - Fix corruption of the return value in cachefiles_read_or_alloc_pages()
   - Fix several fscache cookie issues
   - Fix a fscache queuing race that can trigger a BUG_ON
   - NFS: Fix two use-after-free regressions due to the RPC_TASK_CRED_NOREF flag
   - SUNRPC: Fix a use-after-free regression in rpc_free_client_work()
   - SUNRPC: Fix a race when tearing down the rpc client debugfs directory
   - SUNRPC: Signalled ASYNC tasks need to exit
   - NFSv3: fix rpc receive buffer size for MOUNT call"

* tag 'nfs-for-5.7-5' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv3: fix rpc receive buffer size for MOUNT call
  SUNRPC: 'Directory with parent 'rpc_clnt' already present!'
  NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs
  NFS: Don't use RPC_TASK_CRED_NOREF with delegreturn
  SUNRPC: Signalled ASYNC tasks need to exit
  nfs: fix NULL deference in nfs4_get_valid_delegation
  SUNRPC: fix use-after-free in rpc_free_client_work()
  cachefiles: Fix race between read_waiter and read_copier involving op->to_do
  NFSv4: Fix fscache cookie aux_data to ensure change_attr is included
  NFS: Fix fscache super_cookie allocation
  NFS: Fix fscache super_cookie index_key from changing after umount
  cachefiles: Fix corruption of the return value in cachefiles_read_or_alloc_pages()

Failed async writes that are requeued may not clean up a refcount
on the file, which can result in a leaked open. This scenario arises
very reliably when using persistent handles and a reconnect occurs
while writing.

cifs_writev_requeue only releases the reference if the write fails
(rc != 0). The server->ops->async_writev operation will take its own
reference, so the initial reference can always be released.

Signed-off-by: Adam McCoy <adam@forsedomani.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

Prior to commit e3d3ab64dd66 ("SUNRPC: Use au_rslack when
computing reply buffer size"), there was enough slack in the reply
buffer to commodate filehandles of size 60bytes. However, the real
problem was that the reply buffer size for the MOUNT operation was
not correctly calculated. Received buffer size used the filehandle
size for NFSv2 (32bytes) which is much smaller than the allowed
filehandle size for the v3 mounts.

Fix the reply buffer size (decode arguments size) for the MNT command.

Fixes: 2c94b8eca1a2 ("SUNRPC: Use au_rslack when computing reply buffer size")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

There is a possible race when ep_scan_ready_list() leaves ->rdllist and
->obflist empty for a short period of time although some events are
pending.  It is quite likely that ep_events_available() observes empty
lists and goes to sleep.

Since commit 339ddb53d373 ("fs/epoll: remove unnecessary wakeups of
nested epoll") we are conservative in wakeups (there is only one place
for wakeup and this is ep_poll_callback()), thus ep_events_available()
must always observe correct state of two lists.

The easiest and correct way is to do the final check under the lock.
This does not impact the performance, since lock is taken anyway for
adding a wait entry to the wait queue.

The discussion of the problem can be found here:

   https://lore.kernel.org/linux-fsdevel/a2f22c3c-c25a-4bda-8339-a7bdaf17849e@akamai.com/

In this patch barrierless __set_current_state() is used.  This is safe
since waitqueue_active() is called under the same lock on wakeup side.

Short-circuit for fatal signals (i.e.  fatal_signal_pending() check) is
moved to the line just before actual events harvesting routine.  This is
fully compliant to what is said in the comment of the patch where the
actual fatal_signal_pending() check was added: c257a340ede0 ("fs, epoll:
short circuit fetching events if thread has been killed").

Fixes: 339ddb53d373 ("fs/epoll: remove unnecessary wakeups of nested epoll")
Reported-by: Jason Baron <jbaron@akamai.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Baron <jbaron@akamai.com>
Cc: Khazhismel Kumykov <khazhy@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200505145609.1865152-1-rpenyaev@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Coverity scan noted a redundant null check

Coverity-id: 728517
Reported-by: Coverity <scan-admin@coverity.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>

When we changed the file registration handling, it became important to
iterate the bulk request freeing list for fixed files as well, or we
miss dropping the fixed file reference. If not, we're leaking references,
and we'll get a kworker stuck waiting for file references to disappear.

This also means we can remove the special casing of fixed vs non-fixed
files, we need to iterate for both and we can just rely on
__io_req_aux_free() doing io_put_file() instead of doing it manually.

Fixes: 055895537302 ("io_uring: refactor file register/unregister/update handling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>