Pull xfs fix from Darrick Wong:
 "This fixes a race between a readonly remount process and other
  processes that hold a file IOLOCK on files that previously experienced
  copy on write, that could result in severe filesystem corruption if
  the filesystem is then remounted rw.

  I think this is fairly rare (since the only reliable reproducer I have
  that fits the second criteria is the experimental xfs_scrub program),
  but the race is clear, so we still need to fix this.

  Summary:

   - Fix a data corruption vector that can result from the ro remount
     process failing to clear all speculative preallocations from files
     and the rw remount process not noticing the incomplete cleanup"

* tag 'xfs-5.16-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: remove all COW fork extents when remounting readonly

Pull io_uring fixes from Jens Axboe:
 "A few fixes that are all bound for stable:

   - Two syzbot reports for io-wq that turned out to be separate fixes,
     but ultimately very closely related

   - io_uring task_work running on cancelations"

* tag 'io_uring-5.16-2021-12-10' of git://git.kernel.dk/linux-block:
  io-wq: check for wq exit after adding new worker task_work
  io_uring: ensure task_work gets run as part of cancelations
  io-wq: remove spurious bit clear on task_work addition

Pull btrfs fixes from David Sterba:
 "A few more regression fixes and stable patches, mostly one-liners.

  Regression fixes:

   - fix pointer/ERR_PTR mismatch returned from memdup_user

   - reset dedicated zoned mode relocation block group to avoid using it
     and filling it without any recourse

  Fixes:

   - handle a case to FITRIM range (also to make fstests/generic/260
     work)

   - fix warning when extent buffer state and pages get out of sync
     after an IO error

   - fix transaction abort when syncing due to missing mapping error set
     on metadata inode after inlining a compressed file

   - fix transaction abort due to tree-log and zoned mode interacting in
     an unexpected way

   - fix memory leak of additional extent data when qgroup reservation
     fails

   - do proper handling of slot search call when deleting root refs"

* tag 'for-5.16-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: replace the BUG_ON in btrfs_del_root_ref with proper error handling
  btrfs: zoned: clear data relocation bg on zone finish
  btrfs: free exchange changeset on failures
  btrfs: fix re-dirty process of tree-log nodes
  btrfs: call mapping_set_error() on btree inode with a write error
  btrfs: clear extent buffer uptodate when we fail to write it
  btrfs: fail if fstrim_range->start == U64_MAX
  btrfs: fix error pointer dereference in btrfs_ioctl_rm_dev_v2()

Pull cifs fixes from Steve French:
 "Two cifs/smb3 fixes - one for stable, the other fixes a recently
  reported NTLMSSP auth problem"

* tag '5.16-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix ntlmssp auth when there is no key exchange
  cifs: Fix crash on unload of cifs_arc4.ko

Pull nfsd fixes from Bruce Fields:
 "Fix a race on startup and another in the delegation code.

  The latter has been around for years, but I suspect recent changes may
  have widened the race window a little, so I'd like to go ahead and get
  it in"

* tag 'nfsd-5.16-2' of git://linux-nfs.org/~bfields/linux:
  nfsd: fix use-after-free due to delegation race
  nfsd: Fix nsfd startup race (again)

Pull tracing fixes from Steven Rostedt:
 "Tracing, ftrace and tracefs fixes:

   - Have tracefs honor the gid mount option

   - Have new files in tracefs inherit the parent ownership

   - Have direct_ops unregister when it has no more functions

   - Properly clean up the ops when unregistering multi direct ops

   - Add a sample module to test the multiple direct ops

   - Fix memory leak in error path of __create_synth_event()"

* tag 'trace-v5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix possible memory leak in __create_synth_event() error path
  ftrace/samples: Add module to test multi direct modify interface
  ftrace: Add cleanup to unregister_ftrace_direct_multi
  ftrace: Use direct_ops hash in unregister_ftrace_direct
  tracefs: Set all files to the same group ownership as the mount option
  tracefs: Have new files inherit the ownership of their parent

Pull aio poll fixes from Eric Biggers:
 "Fix three bugs in aio poll, and one issue with POLLFREE more broadly:

   - aio poll didn't handle POLLFREE, causing a use-after-free.

   - aio poll could block while the file is ready.

   - aio poll called eventfd_signal() when it isn't allowed.

   - POLLFREE didn't handle multiple exclusive waiters correctly.

  This has been tested with the libaio test suite, as well as with test
  programs I wrote that reproduce the first two bugs. I am sending this
  pull request myself as no one seems to be maintaining this code"

* tag 'aio-poll-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
  aio: Fix incorrect usage of eventfd_signal_allowed()
  aio: fix use-after-free due to missing POLLFREE handling
  aio: keep poll requests on waitqueue until completed
  signalfd: use wake_up_pollfree()
  binder: use wake_up_pollfree()
  wait: add wake_up_pollfree()

We check IO_WQ_BIT_EXIT before attempting to create a new worker, and
wq exit cancels pending work if we have any. But it's possible to have
a race between the two, where creation checks exit finding it not set,
but we're in the process of exiting. The exit side will cancel pending
creation task_work, but there's a gap where we add task_work after we've
canceled existing creations at exit time.

Fix this by checking the EXIT bit post adding the creation task_work.
If it's set, run the same cancelation that exit does.

Reported-and-tested-by: syzbot+b60c982cb0efc5e05a47@syzkaller.appspotmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If we successfully cancel a work item but that work item needs to be
processed through task_work, then we can be sleeping uninterruptibly
in io_uring_cancel_generic() and never process it. Hence we don't
make forward progress and we end up with an uninterruptible sleep
warning.

While in there, correct a comment that should be IFF, not IIF.

Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

A delegation break could arrive as soon as we've called vfs_setlease.  A
delegation break runs a callback which immediately (in
nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru.  If we
then exit nfs4_set_delegation without hashing the delegation, it will be
freed as soon as the callback is done with it, without ever being
removed from del_recall_lru.

Symptoms show up later as use-after-free or list corruption warnings,
usually in the laundromat thread.

I suspect aba2072f4523 "nfsd: grant read delegations to clients holding
writes" made this bug easier to hit, but I looked as far back as v3.0
and it looks to me it already had the same problem.  So I'm not sure
where the bug was introduced; it may have been there from the beginning.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>