When the creator of SQPOLL io_uring dies (i.e. sqo_task), we don't want
its internals like ->files and ->mm to be poked by the SQPOLL task, it
have never been nice and recently got racy. That can happen when the
owner undergoes destruction and SQPOLL tasks tries to submit new
requests in parallel, and so calls io_sq_thread_acquire*().

That patch halts SQPOLL submissions when sqo_task dies by introducing
sqo_dead flag. Once set, the SQPOLL task must not do any submission,
which is synchronised by uring_lock as well as the new flag.

The tricky part is to make sure that disabling always happens, that
means either the ring is discovered by creator's do_exit() -> cancel,
or if the final close() happens before it's done by the creator. The
last is guaranteed by the fact that for SQPOLL the creator task and only
it holds exactly one file note, so either it pins up to do_exit() or
removed by the creator on the final put in flush. (see comments in
uring_flush() around file->f_count == 2).

One more place that can trigger io_sq_thread_acquire_*() is
__io_req_task_submit(). Shoot off requests on sqo_dead there, even
though actually we don't need to. That's because cancellation of
sqo_task should wait for the request before going any further.

note 1: io_disable_sqo_submit() does io_ring_set_wakeup_flag() so the
caller would enter the ring to get an error, but it still doesn't
guarantee that the flag won't be cleared.

note 2: if final __userspace__ close happens not from the creator
task, the file note will pin the ring until the task dies.

Fixed: b1b6b5a3 ("kernel/io_uring: cancel io_uring before task works")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

files_cancel() should cancel all relevant requests and drop file notes,
so we should never have file notes after that, including on-exit fput
and flush. Add a WARN_ONCE to be sure.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

A simple preparation change inlining io_uring_attempt_task_drop() into
io_uring_flush().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We expect io_rw_reissue() to take place only during submission with
uring_lock held. Add a lockdep annotation to check that invariant.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

waitqueue_active() needs smp_mb() to be in sync with waitqueues
modification, but we miss it in io_cqring_ev_posted*() apart from
cq_wait() case.

Take an smb_mb() out of wq_has_sleeper() making it waitqueue_active(),
and place it a few lines before, so it can synchronise other
waitqueue_active() as well.

The patch doesn't add any additional overhead, so even if there are
no problems currently, it's just safer to have it this way.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

      CPU0                    CPU1
       ----                    ----
  lock(&new->fa_lock);
                               local_irq_disable();
                               lock(&ctx->completion_lock);
                               lock(&new->fa_lock);
  <Interrupt>
    lock(&ctx->completion_lock);

 *** DEADLOCK ***

Move kill_fasync() out of io_commit_cqring() to io_cqring_ev_posted(),
so it doesn't hold completion_lock while doing it. That saves from the
reported deadlock, and it's just nice to shorten the locking time and
untangle nested locks (compl_lock -> wq_head::lock).

Reported-by: syzbot+91ca3f25bd7f795f019c@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Make sure io_iopoll_complete() tries to wake up eventfd, which currently
is skipped together with io_cqring_ev_posted() for non-SQPOLL IOPOLL.

Add an iopoll version of io_cqring_ev_posted(), duplicates a bit of
code, but they actually use different sets of wait queues may be for
better.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

alloc_fixed_file_ref_node() currently returns an ERR_PTR on failure.
io_sqe_files_unregister() expects it to return NULL and since it can only
return -ENOMEM, it makes more sense to change alloc_fixed_file_ref_node()
to behave that way.

Fixes: 1ffc5422 ("io_uring: fix io_sqe_files_unregister() hangs")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Fix follow warning:
fs/io_uring.c:1523:22: warning: variable ‘id’ set but not used
[-Wunused-but-set-variable]
  struct io_identity *id;
                        ^~
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

While io_ring_exit_work() is running new requests of all sorts may be
issued, so it should do a bit more to cancel them, otherwise they may
just get stuck. e.g. in io-wq, in poll lists, etc.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring fds marked O_CLOEXEC and we explicitly cancel all requests
before going through exec, so we don't want to leave task's file
references to not our anymore io_uring instances.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

IOPOLL skips completion locking but keeps it under uring_lock, thus
io_cqring_overflow_flush() and so io_cqring_events() need additional
locking with uring_lock in some cases for IOPOLL.

Remove __io_cqring_overflow_flush() from io_cqring_events(), introduce a
wrapper around flush doing needed synchronisation and call it by hand.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_req_task_submit() might be called for IOPOLL, do the fail path under
uring_lock to comply with IOPOLL synchronisation based solely on it.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For cancelling io_uring requests it needs either to be able to run
currently enqueued task_works or having it shut down by that moment.
Otherwise io_uring_cancel_files() may be waiting for requests that won't
ever complete.

Go with the first way and do cancellations before setting PF_EXITING and
so before putting the task_work infrastructure into a transition state
where task_work_run() would better not be called.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_sqe_files_unregister() uninterruptibly waits for enqueued ref nodes,
however requests keeping them may never complete, e.g. because of some
userspace dependency. Make sure it's interruptible otherwise it would
hang forever.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Setting a new reference node to a file data is not trivial, don't repeat
it, add and use a helper.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If we COW the identity, we assume that ->mm never changes. But this
isn't true of multiple processes end up sharing the ring. Hence treat
id->mm like like any other process compontent when it comes to the
identity mapping. This is pretty trivial, just moving the existing grab
into io_grab_identity(), and including a check for the match.

Cc: stable@vger.kernel.org # 5.10
Fixes: 1e6fa521 ("io_uring: COW io_identity on mismatch")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>:
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>:
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Since commit 36e2c742 ("fs: don't allow splice read/write without
explicit ops") we've required that file operation structures explicitly
enable splice support, rather than falling back to the default handlers.

Most /proc files use the indirect 'struct proc_ops' to describe their
file operations, and were fixed up to support splice earlier in commits
40be821d..b24c30c6, but the mountinfo files interact with the
VFS directly using their own 'struct file_operations' and got missed as
a result.

This adds the necessary support for splice to work for /proc/*/mountinfo
and friends.
Reported-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Reported-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=209971
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull NTB fixes from Jon Mason:
 "Bug fix for IDT NTB and Intel NTB LTR management support"

* tag 'ntb-5.11' of git://github.com/jonmason/ntb:
  ntb: intel: add Intel NTB LTR vendor support for gen4 NTB
  ntb: idt: fix error check in ntb_hw_idt.c

Pull crypto fixes from Herbert Xu:
 "Fix a number of autobuild failures due to missing Kconfig
  dependencies"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: qat - add CRYPTO_AES to Kconfig dependencies
  crypto: keembay - Add dependency on HAS_IOMEM
  crypto: keembay - CRYPTO_DEV_KEEMBAY_OCS_AES_SM4 should depend on ARCH_KEEMBAY

Pull objtool fix from Ingo Molnar:
 "Fix a segfault that occurs when built with Clang"

* tag 'objtool-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix seg fault with Clang non-section symbols

Pull locking fixes from Ingo Molnar:
 "Misc fixes/updates:

   - Fix static keys usage in module __init sections

   - Add separate MAINTAINERS entry for static branches/calls

   - Fix lockdep splat with CONFIG_PREEMPTIRQ_EVENTS=y tracing"

* tag 'locking-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  softirq: Avoid bad tracing / lockdep interaction
  jump_label/static_call: Add MAINTAINERS
  jump_label: Fix usage in module __init

Pull timer fixes from Ingo Molnar:
 "Update/fix two CPU sanity checks in the hotplug and the boot code, and
  fix a typo in the Kconfig help text.

  [ Context: the first two commits are the result of an ongoing
    annotation+review work of (intentional) tick_do_timer_cpu() data
    races reported by KCSAN, but the annotations aren't fully cooked
    yet ]"

* tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill"
  tick/sched: Remove bogus boot "safety" check
  tick: Remove pointless cpu valid check in hotplug code

Pull scheduler fix from Ingo Molnar:
 "Fix a context switch performance regression"

* tag 'sched-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Optimize finish_lock_switch()

Commit c9a3c4e6 ("mfd: ab8500-debugfs: Remove extraneous curly
brace") removed a left-over curly brace that caused build failures, but
Joe Perches points out that the subsequent 'seq_putc()' should also be
removed, because the commit that caused all these problems already added
the final '\n' to the seq_printf() above it.
Reported-by: Joe Perches <joe@perches.com>
Fixes: 886c8121 ("mfd: ab8500-debugfs: Remove the racy fiddling with irq_desc")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull PCI fixes from Bjorn Helgaas:

 - Fix a tegra enumeration regression (Rob Herring)

 - Fix a designware-host check that warned on *success*, not failure
   (Alexander Lobakin)

* tag 'pci-v5.11-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: dwc: Fix inverted condition of DMA mask setup warning
  PCI: tegra: Fix host link initialization

Clang errors:

  drivers/mfd/ab8500-debugfs.c:1526:2: error: non-void function does not return a value [-Werror,-Wreturn-type]
          }
          ^
  drivers/mfd/ab8500-debugfs.c:1528:2: error: expected identifier or '('
  return 0;
          ^
  drivers/mfd/ab8500-debugfs.c:1529:1: error: extraneous closing brace ('}')
  }
  ^
  3 errors generated.

The cleanup in ab8500_interrupts_show left a curly brace around, remove
it to fix the error.

Fixes: 886c8121 ("mfd: ab8500-debugfs: Remove the racy fiddling with irq_desc")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 660c4865 ("PCI: dwc: Set 32-bit DMA mask for MSI target address
allocation") added dma_mask_set() call to explicitly set 32-bit DMA mask
for MSI message mapping, but for now it throws a warning on ret == 0, while
dma_set_mask() returns 0 in case of success.

Fix this by inverting the condition.

[bhelgaas: join string to make it greppable]
Fixes: 660c4865 ("PCI: dwc: Set 32-bit DMA mask for MSI target address allocation")
Link: https://lore.kernel.org/r/20201222150708.67983-1-alobakin@pm.meSigned-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Commit b9ac0f9d ("PCI: dwc: Move dw_pcie_setup_rc() to DWC common
code") broke enumeration of downstream devices on Tegra:

In non-working case (next-20201211):

  0001:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad2 (rev a1)
  0001:01:00.0 SATA controller: Marvell Technology Group Ltd. Device 9171 (rev 13)
  0005:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1)

In working case (v5.10-rc7):

  0001:00:00.0 PCI bridge: Molex Incorporated Device 1ad2 (rev a1)
  0001:01:00.0 SATA controller: Marvell Technology Group Ltd. Device 9171 (rev 13)
  0005:00:00.0 PCI bridge: Molex Incorporated Device 1ad0 (rev a1)
  0005:01:00.0 PCI bridge: PLX Technology, Inc. Device 3380 (rev ab)
  0005:02:02.0 PCI bridge: PLX Technology, Inc. Device 3380 (rev ab)
  0005:03:00.0 USB controller: PLX Technology, Inc. Device 3380 (rev ab)

The problem seems to be dw_pcie_setup_rc() is now called twice before and
after the link up handling. The fix is to move Tegra's link up handling to
.start_link() function like other DWC drivers. Tegra is a bit more
complicated than others as it re-inits the whole DWC controller to retry
the link. With this, the initialization ordering is restored to match the
prior sequence.

Fixes: b9ac0f9d ("PCI: dwc: Move dw_pcie_setup_rc() to DWC common code")
Link: https://lore.kernel.org/r/20201218143905.1614098-1-robh@kernel.orgReported-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Tested-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Vidya Sagar <vidyas@nvidia.com>

clang (quite rightly) complains fairly loudly about the newly added
mpc1_get_mpc_out_mux() function returning an uninitialized value if the
'opp_id' checks don't pass.

This may not happen in practice, but the code really shouldn't return
garbage if the sanity checks don't pass.

So just initialize 'val' to zero to avoid the issue.

Fixes: 110b055b ("drm/amd/display: add getter routine to retrieve mpcc mux")
Cc: Josip Pavic <Josip.Pavic@amd.com>
Cc: Bindu Ramamurthy <bindu.r@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more perf tools updates from Arnaldo Carvalho de Melo:

 - Refactor 'perf stat' per CPU/socket/die/thread aggregation fixing use
   cases in ARM machines.

 - Fix memory leak when synthesizing SDT probes in 'perf probe'.

 - Update kernel header copies related to KVM, epol_pwait. msr-index and
   powerpc and s390 syscall tables.

* tag 'perf-tools-2020-12-24' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (24 commits)
  perf probe: Fix memory leak when synthesizing SDT probes
  perf stat aggregation: Add separate thread member
  perf stat aggregation: Add separate core member
  perf stat aggregation: Add separate die member
  perf stat aggregation: Add separate socket member
  perf stat aggregation: Add separate node member
  perf stat aggregation: Start using cpu_aggr_id in map
  perf cpumap: Drop in cpu_aggr_map struct
  perf cpumap: Add new map type for aggregation
  perf stat: Replace aggregation ID with a struct
  perf cpumap: Add new struct for cpu aggregation
  perf cpumap: Use existing allocator to avoid using malloc
  perf tests: Improve topology test to check all aggregation types
  perf tools: Update s390's syscall.tbl copy from the kernel sources
  perf tools: Update powerpc's syscall.tbl copy from the kernel sources
  perf s390: Move syscall.tbl check into check-headers.sh
  perf powerpc: Move syscall.tbl check to check-headers.sh
  tools headers UAPI: Synch KVM's svm.h header with the kernel
  tools kvm headers: Update KVM headers from the kernel sources
  tools headers UAPI: Sync KVM's vmx.h header with the kernel sources
  ...

Pull coccinelle updates from Julia Lawall.

* 'for-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jlawall/linux:
  scripts: coccicheck: Correct usage of make coccicheck
  coccinelle: update expiring email addresses
  coccinnelle: Remove ptr_ret script
  kbuild: do not use scripts/ld-version.sh for checking spatch version
  remove boolinit.cocci

Commit 64a1b95b ("genirq: Restrict export of irq_to_desc()") removed
the export of irq_to_desc() unless powerpc KVM is being built, because
there is still a use of irq_to_desc() in modular code there.

However it used:

  #ifdef CONFIG_KVM_BOOK3S_64_HV

Which doesn't work when that symbol is =m, leading to a build failure:

  ERROR: modpost: "irq_to_desc" [arch/powerpc/kvm/kvm-hv.ko] undefined!

Fix it by checking for the definedness of the correct symbol which is
CONFIG_KVM_BOOK3S_64_HV_MODULE.

Fixes: 64a1b95b ("genirq: Restrict export of irq_to_desc()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull misc vfs updates from Al Viro:
 "Assorted patches from previous cycle(s)..."

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix hostfs_open() use of ->f_path.dentry
  Make sure that make_create_in_sticky() never sees uninitialized value of dir_mode
  fs: Kill DCACHE_DONTCACHE dentry even if DCACHE_REFERENCED is set
  fs: Handle I_DONTCACHE in iput_final() instead of generic_drop_inode()
  fs/namespace.c: WARN if mnt_count has become negative

Pull documentation fixes from Jonathan Corbet:
 "A small set of late-arriving, small documentation fixes"

* tag 'docs-5.11-2' of git://git.lwn.net/linux:
  docs: admin-guide: Fix default value of max_map_count in sysctl/vm.rst
  Documentation/submitting-patches: Document the SoB chain
  Documentation: process: Correct numbering
  docs: submitting-patches: Trivial - fix grammatical error

Pull ext4 updates from Ted Ts'o:
 "Various bug fixes and cleanups for ext4; no new features this cycle"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (29 commits)
  ext4: remove unnecessary wbc parameter from ext4_bio_write_page
  ext4: avoid s_mb_prefetch to be zero in individual scenarios
  ext4: defer saving error info from atomic context
  ext4: simplify ext4 error translation
  ext4: move functions in super.c
  ext4: make ext4_abort() use __ext4_error()
  ext4: standardize error message in ext4_protect_reserved_inode()
  ext4: remove redundant sb checksum recomputation
  ext4: don't remount read-only with errors=continue on reboot
  ext4: fix deadlock with fs freezing and EA inodes
  jbd2: add a helper to find out number of fast commit blocks
  ext4: make fast_commit.h byte identical with e2fsprogs/fast_commit.h
  ext4: fix fall-through warnings for Clang
  ext4: add docs about fast commit idempotence
  ext4: remove the unused EXT4_CURRENT_REV macro
  ext4: fix an IS_ERR() vs NULL check
  ext4: check for invalid block size early when mounting a file system
  ext4: fix a memory leak of ext4_free_data
  ext4: delete nonsensical (commented-out) code inside ext4_xattr_block_set()
  ext4: update ext4_data_block_valid related comments
  ...

Pull smack fix from Casey Schaufler:
 "Provide a fix for the incorrect handling of privilege in the face of
  io_uring's use of kernel threads. That invalidated an long standing
  assumption regarding the privilege of kernel threads.

  The fix is simple and safe. It was provided by Jens Axboe and has been
  tested"

* tag 'Smack-for-5.11-io_uring-fix' of git://github.com/cschaufler/smack-next:
  Smack: Handle io_uring kernel thread privileges

Pull RISC-V fix from Palmer Dabbelt
 "Avoid trying to initialize memory regions outside the usable range"

* tag 'riscv-for-linus-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Fix usage of memblock_enforce_memory_limit

Pull powerpc fixes from Michael Ellerman:

 - Four commits fixing various things in the new C VDSO code

 - One fix for a 32-bit VMAP stack bug

 - Two minor build fixes

Thanks to Cédric Le Goater, Christophe Leroy, and Will Springer.

* tag 'powerpc-5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/32: Fix vmap stack - Properly set r1 before activating MMU on syscall too
  powerpc/vdso: Fix DOTSYM for 32-bit LE VDSO
  powerpc/vdso: Don't pass 64-bit ABI cflags to 32-bit VDSO
  powerpc/vdso: Block R_PPC_REL24 relocations
  powerpc/smp: Add __init to init_big_cores()
  powerpc/time: Force inlining of get_tb()
  powerpc/boot: Fix build of dts/fsl