Merge tag 'hyperv-fixes-signed-20210402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V fixes from Wei Liu:
 "One fix from Lu Yunlong for a double free in hvfb_probe"

* tag 'hyperv-fixes-signed-20210402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  video: hyperv_fb: Fix a double free in hvfb_probe

Merge tag 'driver-core-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fix from Greg KH:
 "Here is a single driver core fix for a reported problem with differed
  probing. It has been in linux-next for a while with no reported
  problems"

* tag 'driver-core-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core: clear deferred probe reason on probe retry

Pull char/misc driver fixes from Greg KH:
 "Here are a few small driver char/misc changes for 5.12-rc6.

  Nothing major here, a few fixes for reported issues:

   - interconnect fixes for problems found

   - fbcon syzbot-found fix

   - extcon fixes

   - firmware stratix10 bugfix

   - MAINTAINERS file update.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  drivers: video: fbcon: fix NULL dereference in fbcon_cursor()
  mei: allow map and unmap of client dma buffer only for disconnected client
  MAINTAINERS: Add linux-phy list and patchwork
  interconnect: Fix kerneldoc warning
  firmware: stratix10-svc: reset COMMAND_RECONFIG_FLAG_PARTIAL to 0
  extcon: Fix error handling in extcon_dev_register
  extcon: Add stubs for extcon_register_notifier_all() functions
  interconnect: core: fix error return code of icc_link_destroy()
  interconnect: qcom: msm8939: remove rpm-ids from non-RPM nodes

Pull staging driver fixes from Greg KH:
 "Here are two rtl8192e staging driver fixes for reported problems.

  Both of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: rtl8192e: Change state information from u16 to u8
  staging: rtl8192e: Fix incorrect source in memcpy()

Pull serial driver fix from Greg KH:
 "Here is a single serial driver fix for 5.12-rc6. Is is a revert of a
  change that showed up in 5.9 that has been reported to cause problems.

  It has been in linux-next for a while with no reported issues"

* tag 'tty-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  soc: qcom-geni-se: Cleanup the code to remove proxy votes

Pull USB fixes from Greg KH:
 "Here are a few small USB driver fixes for 5.12-rc6 to resolve reported
  problems.

  They include:

   - a number of cdc-acm fixes for reported problems. It seems more
     people are using this driver lately...

   - dwc3 driver fixes for reported problems, and fixes for the fixes :)

   - dwc2 driver fixes for reported issues.

   - musb driver fix.

   - new USB quirk additions.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (23 commits)
  usb: dwc2: Prevent core suspend when port connection flag is 0
  usb: dwc2: Fix HPRT0.PrtSusp bit setting for HiKey 960 board.
  usb: musb: Fix suspend with devices connected for a64
  usb: xhci-mtk: fix broken streams issue on 0.96 xHCI
  usb: dwc3: gadget: Clear DEP flags after stop transfers in ep disable
  usbip: vhci_hcd fix shift out-of-bounds in vhci_hub_control()
  USB: quirks: ignore remote wake-up on Fibocom L850-GL LTE modem
  USB: cdc-acm: do not log successful probe on later errors
  USB: cdc-acm: always claim data interface
  USB: cdc-acm: use negation for NULL checks
  USB: cdc-acm: clean up probe error labels
  USB: cdc-acm: drop redundant driver-data reset
  USB: cdc-acm: drop redundant driver-data assignment
  USB: cdc-acm: fix use-after-free after probe failure
  USB: cdc-acm: fix double free on probe failure
  USB: cdc-acm: downgrade message to debug
  USB: cdc-acm: untangle a circular dependency between callback and softint
  cdc-acm: fix BREAK rx code path adding necessary calls
  usb: gadget: udc: amd5536udc_pci fix null-ptr-dereference
  usb: dwc3: pci: Enable dis_uX_susphy_quirk for Intel Merrifield
  ...

Pull SCSI fix from James Bottomley:
 "A single fix to iscsi for a rare race condition which can cause a
  kernel panic"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: iscsi: Fix race condition between login and sync thread

Pull block fixes from Jens Axboe:

 - Remove comment that never came to fruition in 22 years of development
   (Christoph)

 - Remove unused request flag (Christoph)

 - Fix for null_blk fake timeout handling (Damien)

 - Fix for IOCB_NOWAIT being ignored for O_DIRECT on raw bdevs (Pavel)

 - Error propagation fix for multiple split bios (Yufen)

* tag 'block-5.12-2021-04-02' of git://git.kernel.dk/linux-block:
  block: remove the unused RQF_ALLOCED flag
  block: update a few comments in uapi/linux/blkpg.h
  block: don't ignore REQ_NOWAIT for direct IO
  null_blk: fix command timeout completion handling
  block: only update parent bi_status when bio fail

Pull io_uring fixes from Jens Axboe:
 "Nothing really major in here, and finally nothing really related to
  signals. A few minor fixups related to the threading changes, and some
  general fixes, that's it.

  There's the pending gdb-get-confused-about-arch, but that's more of a
  cosmetic issue, nothing that hinder use of it. And given that other
  archs will likely be affected by that oddity too, better to postpone
  any changes there until 5.13 imho"

* tag 'io_uring-5.12-2021-04-02' of git://git.kernel.dk/linux-block:
  io_uring: move reissue into regular IO path
  io_uring: fix EIOCBQUEUED iter revert
  io_uring/io-wq: protect against sprintf overflow
  io_uring: don't mark S_ISBLK async work as unbounded
  io_uring: drop sqd lock before handling signals for SQPOLL
  io_uring: handle setup-failed ctx in kill_timeouts
  io_uring: always go for cancellation spin on exec

Pull ACPI fixes from Rafael Wysocki:
 "These fix an ACPI tables management issue, an issue related to the
  ACPI enumeration of devices and CPU wakeup in the ACPI processor
  driver.

  Specifics:

   - Ensure that the memory occupied by ACPI tables on x86 will always
     be reserved to prevent it from being allocated for other purposes
     which was possible in some cases (Rafael Wysocki).

   - Fix the ACPI device enumeration code to prevent it from attempting
     to evaluate the _STA control method for devices with unmet
     dependencies which is likely to fail (Hans de Goede).

   - Fix the handling of CPU0 wakeup in the ACPI processor driver to
     prevent CPU0 online failures from occurring (Vitaly Kuznetsov)"

* tag 'acpi-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()
  ACPI: scan: Fix _STA getting called on devices with unmet dependencies
  ACPI: tables: x86: Reserve memory occupied by ACPI tables

Pull power management fixes from Rafael Wysocki:
 "These fix a race condition and an ordering issue related to using
  device links in the runtime PM framework and two kerneldoc comments in
  cpufreq.

  Specifics:

   - Fix race condition related to the handling of supplier devices
     during consumer device probe and fix the order of decrementation of
     two related reference counters in the runtime PM core code handling
     supplier devices (Adrian Hunter).

   - Fix kerneldoc comments in cpufreq that have not been updated along
     with the functions documented by them (Geert Uytterhoeven)"

* tag 'pm-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM: runtime: Fix race getting/putting suppliers at probe
  PM: runtime: Fix ordering in pm_runtime_get_suppliers()
  cpufreq: Fix scaling_{available,boost}_frequencies_show() comments

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The big top of the file comment talk about grand plans that never
happened, so remove them to not confuse the readers.  Also mark the
devname and volname fields as ignored as they were never used by the
kernel.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull tracing fix from Steven Rostedt:
 "Fix stack trace entry size to stop showing garbage

  The macro that creates both the structure and the format displayed to
  user space for the stack trace event was changed a while ago to fix
  the parsing by user space tooling. But this change also modified the
  structure used to store the stack trace event. It changed the caller
  array field from [0] to [8].

  Even though the size in the ring buffer is dynamic and can be
  something other than 8 (user space knows how to handle this), the 8
  extra words was not accounted for when reserving the event on the ring
  buffer, and added 8 more entries, due to the calculation of
  "sizeof(*entry) + nr_entries * sizeof(long)", as the sizeof(*entry)
  now contains 8 entries.

  The size of the caller field needs to be subtracted from the size of
  the entry to create the correct allocation size"

* tag 'trace-v5.12-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix stack trace event size

It's non-obvious how retry is done for block backed files, when it happens
off the kiocb done path. It also makes it tricky to deal with the iov_iter
handling.

Just mark the req as needing a reissue, and handling it from the
submission path instead. This makes it directly obvious that we're not
re-importing the iovec from userspace past the submit point, and it means
that we can just reuse our usual -EAGAIN retry path from the read/write
handling.

At some point in the future, we'll gain the ability to always reliably
return -EAGAIN through the stack. A previous attempt on the block side
didn't pan out and got reverted, hence the need to check for this
information out-of-band right now.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

* acpi-tables:
  ACPI: tables: x86: Reserve memory occupied by ACPI tables

* acpi-scan:
  ACPI: scan: Fix _STA getting called on devices with unmet dependencies

* pm-cpufreq:
  cpufreq: Fix scaling_{available,boost}_frequencies_show() comments

If IOCB_NOWAIT is set on submission, then that needs to get propagated to
REQ_NOWAIT on the block side. Otherwise we completely lose this
information, and any issuer of IOCB_NOWAIT IO will potentially end up
blocking on eg request allocation on the storage side.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull LTO fix from Kees Cook:
 "It seems that there is a bug in ld.bfd when doing module section
  merging.

  As explicit merging is only needed for LTO, the work-around is to only
  do it under LTO, leaving the original section layout choices alone
  under normal builds:

   - Only perform explicit module section merges under LTO (Sean
     Christopherson)"

* tag 'lto-v5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: lto: Merge module sections if and only if CONFIG_LTO_CLANG is enabled

Merge module sections only when using Clang LTO. With ld.bfd, merging
sections does not appear to update the symbol tables for the module,
e.g. 'readelf -s' shows the value that a symbol would have had, if
sections were not merged. ld.lld does not show this problem.

The stale symbol table breaks gdb's function disassembler, and presumably
other things, e.g.

  gdb -batch -ex "file arch/x86/kvm/kvm.ko" -ex "disassemble kvm_init"

reads the wrong bytes and dumps garbage.

Fixes: dd277622 ("kbuild: lto: merge module sections")
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210322234438.502582-1-seanjc@google.com

Pull kvm fixes from Paolo Bonzini:
 "It's a bit larger than I (and probably you) would like by the time we
  get to -rc6, but perhaps not entirely unexpected since the changes in
  the last merge window were larger than usual.

  x86:
   - Fixes for missing TLB flushes with TDP MMU

   - Fixes for race conditions in nested SVM

   - Fixes for lockdep splat with Xen emulation

   - Fix for kvmclock underflow

   - Fix srcdir != builddir builds

   - Other small cleanups

  ARM:
   - Fix GICv3 MMIO compatibility probing

   - Prevent guests from using the ARMv8.4 self-hosted tracing
     extension"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  selftests: kvm: Check that TSC page value is small after KVM_SET_CLOCK(0)
  KVM: x86: Prevent 'hv_clock->system_time' from going negative in kvm_guest_time_update()
  KVM: x86: disable interrupts while pvclock_gtod_sync_lock is taken
  KVM: x86: reduce pvclock_gtod_sync_lock critical sections
  KVM: SVM: ensure that EFER.SVME is set when running nested guest or on nested vmexit
  KVM: SVM: load control fields from VMCB12 before checking them
  KVM: x86/mmu: Don't allow TDP MMU to yield when recovering NX pages
  KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping
  KVM: x86/mmu: Ensure TLBs are flushed when yielding during GFN range zap
  KVM: make: Fix out-of-source module builds
  selftests: kvm: make hardware_disable_test less verbose
  KVM: x86/vPMU: Forbid writing to MSR_F15H_PERF MSRs when guest doesn't have X86_FEATURE_PERFCTR_CORE
  KVM: x86: remove unused declaration of kvm_write_tsc()
  KVM: clean up the unused argument
  tools/kvm_stat: Add restart delay
  KVM: arm64: Fix CPU interface MMIO compatibility detection
  KVM: arm64: Disable guest access to trace filter controls
  KVM: arm64: Hide system instruction access to Trace registers

Pull drm fixes from Dave Airlie:
 "Things have settled down in time for Easter, a random smattering of
  small fixes across a few drivers.

  I'm guessing though there might be some i915 and misc fixes out there
  I haven't gotten yet, but since today is a public holiday here, I'm
  sending this early so I can have the day off, I'll see if more
  requests come in and decide what to do with them later.

  amdgpu:
   - Polaris idle power fix
   - VM fix
   - Vangogh S3 fix
   - Fixes for non-4K page sizes

  amdkfd:
   - dqm fence memory corruption fix

  tegra:
   - lockdep warning fix
   - runtine PM reference fix
   - display controller fix
   - PLL Fix

  imx:
   - memory leak in error path fix
   - LDB driver channel registration fix
   - oob array warning in LDB driver

  exynos
   - unused header file removal"

* tag 'drm-fixes-2021-04-02' of git://anongit.freedesktop.org/drm/drm:
  drm/amdgpu: check alignment on CPU page for bo map
  drm/amdgpu: Set a suitable dev_info.gart_page_size
  drm/amdgpu/vangogh: don't check for dpm in is_dpm_running when in suspend
  drm/amdkfd: dqm fence memory corruption
  drm/tegra: sor: Grab runtime PM reference across reset
  drm/tegra: dc: Restore coupling of display controllers
  gpu: host1x: Use different lock classes for each client
  drm/tegra: dc: Don't set PLL clock to 0Hz
  drm/amdgpu: fix offset calculation in amdgpu_vm_bo_clear_mappings()
  drm/amd/pm: no need to force MCLK to highest when no display connected
  drm/exynos/decon5433: Remove the unused include statements
  drm/imx: imx-ldb: fix out of bounds array access warning
  drm/imx: imx-ldb: Register LDB channel1 when it is the only channel to be used
  drm/imx: fix memory leak when fails to init

drm/imx: imx-drm-core and imx-ldb fixes

Fix a memory leak in an error path during DRM device initialization,
fix the LDB driver to register channel 1 even if channel 0 is unused,
and fix an out of bounds array access warning in the LDB driver.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210401092235.GA13586@pengutronix.de

drm/tegra: Fixes for v5.12-rc6

This contains a couple of fixes for various issues such as lockdep
warnings, runtime PM references, coupled display controllers and
misconfigured PLLs.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thierry Reding <thierry.reding@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210401163352.3348296-1-thierry.reding@gmail.com

Commit cbc3b92c fixed an issue to modify the macros of the stack trace
event so that user space could parse it properly. Originally the stack
trace format to user space showed that the called stack was a dynamic
array. But it is not actually a dynamic array, in the way that other
dynamic event arrays worked, and this broke user space parsing for it. The
update was to make the array look to have 8 entries in it. Helper
functions were added to make it parse it correctly, as the stack was
dynamic, but was determined by the size of the event stored.

Although this fixed user space on how it read the event, it changed the
internal structure used for the stack trace event. It changed the array
size from [0] to [8] (added 8 entries). This increased the size of the
stack trace event by 8 words. The size reserved on the ring buffer was the
size of the stack trace event plus the number of stack entries found in
the stack trace. That commit caused the amount to be 8 more than what was
needed because it did not expect the caller field to have any size. This
produced 8 entries of garbage (and reading random data) from the stack
trace event:

          <idle>-0       [002] d... 1976396.837549: <stack trace>
 => trace_event_raw_event_sched_switch
 => __traceiter_sched_switch
 => __schedule
 => schedule_idle
 => do_idle
 => cpu_startup_entry
 => secondary_startup_64_no_verify
 => 0xc8c5e150ffff93de
 => 0xffff93de
 => 0
 => 0
 => 0xc8c5e17800000000
 => 0x1f30affff93de
 => 0x00000004
 => 0x200000000

Instead, subtract the size of the caller field from the size of the event
to make sure that only the amount needed to store the stack trace is
reserved.

Link: https://lore.kernel.org/lkml/your-ad-here.call-01617191565-ext-9692@work.hours/

Cc: stable@vger.kernel.org
Fixes: cbc3b92c ("tracing: Set kernel_stack's caller size properly")
Reported-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull sound fixes from Takashi Iwai:
 "Things seem calming down, only usual device-specific fixes for
  HD-audio and USB-audio at this time"

* tag 'sound-5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/realtek: fix mute/micmute LEDs for HP 640 G8
  ALSA: hda: Add missing sanity checks in PM prepare/complete callbacks
  ALSA: hda: Re-add dropped snd_poewr_change_state() calls
  ALSA: usb-audio: Apply sample rate quirk to Logitech Connect
  ALSA: hda/realtek: call alc_update_headset_mode() in hp_automute_hook
  ALSA: hda/realtek: fix a determine_headset_type issue for a Dell AIO

Pull tomory fix from Tetsuo Handa:
 "An update on 'tomoyo: recognize kernel threads correctly' from Jens
  Axboe to not special case PF_IO_WORKER for PF_KTHREAD"

* tag 'tomoyo-pr-20210401' of git://git.osdn.net/gitroot/tomoyo/tomoyo-test1:
  tomoyo: don't special case PF_IO_WORKER for PF_KTHREAD

Pull XArray fixes from Matthew Wilcox:
 "My apologies for the lateness of this. I had a bug reported in the
  test suite, and when I started working on it, I realised I had two
  fixes sitting in the xarray tree since last November. Anyway,
  everything here is fixes, apart from adding xa_limit_16b. The test
  suite passes.

  Summary:

   - Fix a bug when splitting to a non-zero order

   - Documentation fix

   - Add a predefined 16-bit allocation limit

   - Various test suite fixes"

* tag 'xarray-5.12' of git://git.infradead.org/users/willy/xarray:
  idr test suite: Improve reporting from idr_find_test_1
  idr test suite: Create anchor before launching throbber
  idr test suite: Take RCU read lock in idr_find_test_1
  radix tree test suite: Register the main thread with the RCU library
  radix tree test suite: Fix compilation
  XArray: Add xa_limit_16b
  XArray: Fix splitting to non-zero orders
  XArray: Fix split documentation

iov_iter_revert() is done in completion handlers that happensf before
read/write returns -EIOCBQUEUED, no need to repeat reverting afterwards.
Moreover, even though it may appear being just a no-op, it's actually
races with 1) user forging a new iovec of a different size 2) reissue,
that is done via io-wq continues completely asynchronously.

Fixes: 3e6a0d3c ("io_uring: fix -EAGAIN retry with IOPOLL")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

task_pid may be large enough to not fit into the left space of
TASK_COMM_LEN-sized buffers and overflow in sprintf. We not so care
about uniqueness, so replace it with safer snprintf().
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1702c6145d7e1c46fbc382f28334c02e1a3d3994.1617267273.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

S_ISBLK is marked as unbounded work for async preparation, because it
doesn't match S_ISREG. That is incorrect, as any read/write to a block
device is also a bounded operation. Fix it up and ensure that S_ISBLK
isn't marked unbounded.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Memory backed or zoned null block devices may generate actual request
timeout errors due to the submission path being blocked on memory
allocation or zone locking. Unlike fake timeouts or injected timeouts,
the request submission path will call blk_mq_complete_request() or
blk_mq_end_request() for these real timeout errors, causing a double
completion and use after free situation as the block layer timeout
handler executes blk_mq_rq_timed_out() and __blk_mq_free_request() in
blk_mq_check_expired(). This problem often triggers a NULL pointer
dereference such as:

BUG: kernel NULL pointer dereference, address: 0000000000000050
RIP: 0010:blk_mq_sched_mark_restart_hctx+0x5/0x20
...
Call Trace:
  dd_finish_request+0x56/0x80
  blk_mq_free_request+0x37/0x130
  null_handle_cmd+0xbf/0x250 [null_blk]
  ? null_queue_rq+0x67/0xd0 [null_blk]
  blk_mq_dispatch_rq_list+0x122/0x850
  __blk_mq_do_dispatch_sched+0xbb/0x2c0
  __blk_mq_sched_dispatch_requests+0x13d/0x190
  blk_mq_sched_dispatch_requests+0x30/0x60
  __blk_mq_run_hw_queue+0x49/0x90
  process_one_work+0x26c/0x580
  worker_thread+0x55/0x3c0
  ? process_one_work+0x580/0x580
  kthread+0x134/0x150
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x1f/0x30

This problem very often triggers when running the full btrfs xfstests
on a memory-backed zoned null block device in a VM with limited amount
of memory.

Avoid this by executing blk_mq_complete_request() in null_timeout_rq()
only for commands that are marked for a fake timeout completion using
the fake_timeout boolean in struct null_cmd. For timeout errors injected
through debugfs, the timeout handler will execute
blk_mq_complete_request()i as before. This is safe as the submission
path does not execute complete requests in this case.

In null_timeout_rq(), also make sure to set the command error field to
BLK_STS_TIMEOUT and to propagate this error through to the request
completion.
Reported-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210331225244.126426-1-damien.lemoal@wdc.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Instead of just reporting an assertion failure, report enough information
that we can start diagnosing exactly went wrong.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

The throbber could race with creation of the anchor entry and cause the
IDR to have zero entries in it, which would cause the test to fail.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

When run on a single CPU, this test would frequently access already-freed
memory.  Due to timing, this bug never showed up on multi-CPU tests.
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Several test runners register individual worker threads with the
RCU library, but neglect to register the main thread, which can lead
to objects being freed while the main thread is in what appears to be
an RCU critical section.
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Commit 496121c0 ("ACPI: processor: idle: Allow probing on platforms
with one ACPI C-state") broke CPU0 hotplug on certain systems, e.g.
I'm observing the following on AWS Nitro (e.g r5b.xlarge but other
instance types are affected as well):

 # echo 0 > /sys/devices/system/cpu/cpu0/online
 # echo 1 > /sys/devices/system/cpu/cpu0/online
 <10 seconds delay>
 -bash: echo: write error: Input/output error

In fact, the above mentioned commit only revealed the problem and did
not introduce it. On x86, to wakeup CPU an NMI is being used and
hlt_play_dead()/mwait_play_dead() loops are prepared to handle it:

	/*
	 * If NMI wants to wake up CPU0, start CPU0.
	 */
	if (wakeup_cpu0())
		start_cpu0();

cpuidle_play_dead() -> acpi_idle_play_dead() (which is now being called on
systems where it wasn't called before the above mentioned commit) serves
the same purpose but it doesn't have a path for CPU0. What happens now on
wakeup is:
 - NMI is sent to CPU0
 - wakeup_cpu0_nmi() works as expected
 - we get back to while (1) loop in acpi_idle_play_dead()
 - safe_halt() puts CPU0 to sleep again.

The straightforward/minimal fix is add the special handling for CPU0 on x86
and that's what the patch is doing.

Fixes: 496121c0 ("ACPI: processor: idle: Allow probing on platforms with one ACPI C-state")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a test for the issue when KVM_SET_CLOCK(0) call could cause
TSC page value to go very big because of a signedness issue around
hv_clock->system_time.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210326155551.17446-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When guest time is reset with KVM_SET_CLOCK(0), it is possible for
'hv_clock->system_time' to become a small negative number. This happens
because in KVM_SET_CLOCK handling we set 'kvm->arch.kvmclock_offset' based
on get_kvmclock_ns(kvm) but when KVM_REQ_CLOCK_UPDATE is handled,
kvm_guest_time_update() does (masterclock in use case):

hv_clock.system_time = ka->master_kernel_ns + v->kvm->arch.kvmclock_offset;

And 'master_kernel_ns' represents the last time when masterclock
got updated, it can precede KVM_SET_CLOCK() call. Normally, this is not a
problem, the difference is very small, e.g. I'm observing
hv_clock.system_time = -70 ns. The issue comes from the fact that
'hv_clock.system_time' is stored as unsigned and 'system_time / 100' in
compute_tsc_page_parameters() becomes a very big number.

Use 'master_kernel_ns' instead of get_kvmclock_ns() when masterclock is in
use and get_kvmclock_base_ns() when it's not to prevent 'system_time' from
going negative.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210331124130.337992-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

pvclock_gtod_sync_lock can be taken with interrupts disabled if the
preempt notifier calls get_kvmclock_ns to update the Xen
runstate information:

   spin_lock include/linux/spinlock.h:354 [inline]
   get_kvmclock_ns+0x25/0x390 arch/x86/kvm/x86.c:2587
   kvm_xen_update_runstate+0x3d/0x2c0 arch/x86/kvm/xen.c:69
   kvm_xen_update_runstate_guest+0x74/0x320 arch/x86/kvm/xen.c:100
   kvm_xen_runstate_set_preempted arch/x86/kvm/xen.h:96 [inline]
   kvm_arch_vcpu_put+0x2d8/0x5a0 arch/x86/kvm/x86.c:4062

So change the users of the spinlock to spin_lock_irqsave and
spin_unlock_irqrestore.

Reported-by: syzbot+b282b65c2c68492df769@syzkaller.appspotmail.com
Fixes: 30b5c851 ("KVM: x86/xen: Add support for vCPU runstate information")
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>