Inspecting the data structures of the function graph tracer, I found that
the overrun value is unsigned long, which is 8 bytes on a 64 bit machine,
and not only that, the depth is an int (4 bytes). The overrun can be simply
an unsigned int (4 bytes) and pack the ftrace_graph_ret structure better.

The depth is moved up next to the func, as it is used more often with func,
and improves cache locality.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

This adds CONFIG_FTRACE_RECORD_RECURSION that will record to a file
"recursed_functions" all the functions that caused recursion while a
callback to the function tracer was running.

Link: https://lkml.kernel.org/r/20201106023548.102375687@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: live-patching@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Now that all callbacks are recursion safe, reverse the meaning of the
RECURSION flag and rename it from RECURSION_SAFE to simply RECURSION.
Now only callbacks that request to have recursion protecting it will
have the added trampoline to do so.

Also remove the outdated comment about "PER_CPU" when determining to
use the ftrace_ops_assist_func.

Link: https://lkml.kernel.org/r/20201028115613.742454631@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.904270143@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh  Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If a ftrace callback requires "rcu_is_watching", then it adds the
FTRACE_OPS_FL_RCU flag and it will not be called if RCU is not "watching".
But this means that it will use a trampoline when called, and this slows
down the function tracing a tad. By checking rcu_is_watching() from within
the callback, it no longer needs the RCU flag set in the ftrace_ops and it
can be safely called directly.

Link: https://lkml.kernel.org/r/20201028115613.591878956@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.711035826@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh  Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.

The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.

Link: https://lkml.kernel.org/r/20201028115613.444477858@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.466892083@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh  Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If for some reason a function is called that triggers the recursion
detection of live patching, trigger a warning. By not executing the live
patch code, it is possible that the old unpatched function will be called
placing the system into an unknown state.

Link: https://lore.kernel.org/r/20201029145709.GD16774@alley
Link: https://lkml.kernel.org/r/20201106023547.312639435@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org
Suggested-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.

The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.

Link: https://lkml.kernel.org/r/20201028115613.291169246@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.122802424@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.

The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.

Link: https://lkml.kernel.org/r/20201028115613.140212174@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.944907560@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh  Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.

The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.

Link: https://lkml.kernel.org/r/20201028115612.990886844@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.720372267@goodmis.org

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh  Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Meyer <thomas@m3y3r.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The preempt_count() is not a simple location in memory, it could be part of
per_cpu code or more. Each access to preempt_count(), or one of its accessor
functions (like in_interrupt()) takes several cycles. By reading
preempt_count() once, and then doing tests to find the context against the
value return is slightly faster than using in_nmi() and in_interrupt().

Link: https://lkml.kernel.org/r/20201028115612.780796355@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.558881845@goodmis.orgSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

To make it easier for ftrace callbacks to have recursion protection, provide
a ftrace_test_recursion_trylock() and ftrace_test_recursion_unlock() helper
that tests for recursion.

Link: https://lkml.kernel.org/r/20201028115612.634927593@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.378584067@goodmis.orgSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Currently, if a callback is registered to a ftrace function and its
ftrace_ops does not have the RECURSION flag set, it is encapsulated in a
helper function that does the recursion for it.

Really, all the callbacks should have their own recursion protection for
performance reasons. But they should not all implement their own. Move the
recursion helpers to global headers, so that all callbacks can use them.

Link: https://lkml.kernel.org/r/20201028115612.460535535@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.166456258@goodmis.orgSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Since the kprobe handlers have protection that prohibits other handlers from
executing in other contexts (like if an NMI comes in while processing a
kprobe, and executes the same kprobe, it will get fail with a "busy"
return). Lockdep is unaware of this protection. Use lockdep's nesting api to
differentiate between locks taken in INT3 context and other context to
suppress the false warnings.

Link: https://lore.kernel.org/r/20201102160234.fa0ae70915ad9e2b21c08b85@kernel.org

Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parse_synth_field() returns a pointer and requires that errors get
surrounded by ERR_PTR(). The ret variable is initialized to zero, but should
never be used as zero, and if it is, it could cause a false return code and
produce a NULL pointer dereference. It makes no sense to set ret to zero.

Set ret to -ENOMEM (the most common error case), and have any other errors
set it to something else. This removes the need to initialize ret on *every*
error branch.

Fixes: 761a8c58 ("tracing, synthetic events: Replace buggy strcat() with seq_buf operations")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The recursion protection of the ring buffer depends on preempt_count() to be
correct. But it is possible that the ring buffer gets called after an
interrupt comes in but before it updates the preempt_count(). This will
trigger a false positive in the recursion code.

Use the same trick from the ftrace function callback recursion code which
uses a "transition" bit that gets set, to allow for a single recursion for
to handle transitions between contexts.

Cc: stable@vger.kernel.org
Fixes: 567cd4da ("ring-buffer: User context bit recursion checking")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The array size is FTRACE_KSTACK_NESTING, so the index FTRACE_KSTACK_NESTING
is illegal too. And fix two typos by the way.

Link: https://lkml.kernel.org/r/20201031085714.2147-1-hqjagain@gmail.comSigned-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

When an interrupt or NMI comes in and switches the context, there's a delay
from when the preempt_count() shows the update. As the preempt_count() is
used to detect recursion having each context have its own bit get set when
tracing starts, and if that bit is already set, it is considered a recursion
and the function exits. But if this happens in that section where context
has changed but preempt_count() has not been updated, this will be
incorrectly flagged as a recursion.

To handle this case, create another bit call TRANSITION and test it if the
current context bit is already set. Flag the call as a recursion if the
TRANSITION bit is already set, and if not, set it and continue. The
TRANSITION bit will be cleared normally on the return of the function that
set it, or if the current context bit is clear, set it and clear the
TRANSITION bit to allow for another transition between the current context
and an even higher one.

Cc: stable@vger.kernel.org
Fixes: edc15caf ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The code that checks recursion will work to only do the recursion check once
if there's nested checks. The top one will do the check, the other nested
checks will see recursion was already checked and return zero for its "bit".
On the return side, nothing will be done if the "bit" is zero.

The problem is that zero is returned for the "good" bit when in NMI context.
This will set the bit for NMIs making it look like *all* NMI tracing is
recursing, and prevent tracing of anything in NMI context!

The simple fix is to return "bit + 1" and subtract that bit on the end to
get the real bit.

Cc: stable@vger.kernel.org
Fixes: edc15caf ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The nesting count of trace_printk allows for 4 levels of nesting. The
nesting counter starts at zero and is incremented before being used to
retrieve the current context's buffer. But the index to the buffer uses the
nesting counter after it was incremented, and not its original number,
which in needs to do.

Link: https://lkml.kernel.org/r/20201029161905.4269-1-hqjagain@gmail.com

Cc: stable@vger.kernel.org
Fixes: 3d9622c1 ("tracing: Add barrier to trace_printk() buffer nesting modification")
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull x86 fixes from Thomas Gleixner:
 "Three fixes all related to #DB:

   - Handle the BTF bit correctly so it doesn't get lost due to a kernel
     #DB

   - Only clear and set the virtual DR6 value used by ptrace on user
     space triggered #DB. A kernel #DB must leave it alone to ensure
     data consistency for ptrace.

   - Make the bitmasking of the virtual DR6 storage correct so it does
     not lose DR_STEP"

* tag 'x86-urgent-2020-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/debug: Fix DR_STEP vs ptrace_get_debugreg(6)
  x86/debug: Only clear/set ->virtual_dr6 for userspace #DB
  x86/debug: Fix BTF handling

Pull timer fixes from Thomas Gleixner:
 "A few fixes for timers/timekeeping:

   - Prevent undefined behaviour in the timespec64_to_ns() conversion
     which is used for converting user supplied time input to
     nanoseconds. It lacked overflow protection.

   - Mark sched_clock_read_begin/retry() to prevent recursion in the
     tracer

   - Remove unused debug functions in the hrtimer and timerlist code"

* tag 'timers-urgent-2020-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Prevent undefined behaviour in timespec64_to_ns()
  timers: Remove unused inline funtion debug_timer_free()
  hrtimer: Remove unused inline function debug_hrtimer_free()
  time/sched_clock: Mark sched_clock_read_begin/retry() as notrace

Pull smp fix from Thomas Gleixner:
 "A single fix for stop machine.

  Mark functions no trace to prevent a crash caused by recursion when
  enabling or disabling a tracer on RISC-V (probably all architectures
  which patch through stop machine)"

* tag 'smp-urgent-2020-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  stop_machine, rcu: Mark functions as notrace

Pull locking fixes from Thomas Gleixner:
 "A couple of locking fixes:

   - Fix incorrect failure injection handling in the fuxtex code

   - Prevent a preemption warning in lockdep when tracking
     local_irq_enable() and interrupts are already enabled

   - Remove more raw_cpu_read() usage from lockdep which causes state
     corruption on !X86 architectures.

   - Make the nr_unused_locks accounting in lockdep correct again"

* tag 'locking-urgent-2020-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix nr_unused_locks accounting
  locking/lockdep: Remove more raw_cpu_read() usage
  futex: Fix incorrect should_fail_futex() handling
  lockdep: Fix preemption WARN for spurious IRQ-enable

Pull char/misc fixes/removals from Greg KH:
 "Here's some small fixes for 5.10-rc2 and a big driver removal.

  The fixes are for some reported issues in the interconnect and
  coresight drivers, nothing major.

  The "big" driver removal is the MIC drivers have been asked to be
  removed as the hardware never shipped and Intel no longer wants to
  maintain something that no one can use. This is welcomed by many as
  the DMA usage of these drivers was "interesting" and the security
  people were starting to question some issues that were starting to be
  found in the codebase.

  Note, one of the subsystems for this driver, the "VOP" code, will
  probably come back in future kernel versions as it was looking to
  potentially solve some PCIe virtualization issues that a number of
  other vendors were wanting to solve. But as-is, this codebase didn't
  work for anyone else so no actual functionality is being removed.

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

* tag 'char-misc-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  coresight: cti: Initialize dynamic sysfs attributes
  coresight: Fix uninitialised pointer bug in etm_setup_aux()
  coresight: add module license
  misc: mic: remove the MIC drivers
  interconnect: qcom: use icc_sync state for sm8[12]50
  interconnect: qcom: Ensure that the floor bandwidth value is enforced
  interconnect: qcom: sc7180: Init BCMs before creating the nodes
  interconnect: qcom: sdm845: Init BCMs before creating the nodes
  interconnect: Aggregate before setting initial bandwidth
  interconnect: qcom: sdm845: Enable keepalive for the MM1 BCM

Merge tag 'driver-core-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and documentation fixes from Greg KH:
 "Here is one tiny debugfs change to fix up an API where the last user
  was successfully fixed up in 5.10-rc1 (so it couldn't be merged
  earlier), and a much larger Documentation/ABI/ update to the files so
  they can be automatically parsed by our tools.

  The Documentation/ABI/ updates are just formatting issues, small ones
  to bring the files into parsable format, and have been acked by
  numerous subsystem maintainers and the documentation maintainer. I
  figured it was good to get this into 5.10-rc2 to help wih the merge
  issues that would arise if these were to stick in linux-next until
  5.11-rc1.

  The debugfs change has been in linux-next for a long time, and the
  Documentation updates only for the last linux-next release"

* tag 'driver-core-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (40 commits)
  scripts: get_abi.pl: assume ReST format by default
  docs: ABI: sysfs-class-led-trigger-pattern: remove hw_pattern duplication
  docs: ABI: sysfs-class-backlight: unify ABI documentation
  docs: ABI: sysfs-c2port: remove a duplicated entry
  docs: ABI: sysfs-class-power: unify duplicated properties
  docs: ABI: unify /sys/class/leds/<led>/brightness documentation
  docs: ABI: stable: remove a duplicated documentation
  docs: ABI: change read/write attributes
  docs: ABI: cleanup several ABI documents
  docs: ABI: sysfs-bus-nvdimm: use the right format for ABI
  docs: ABI: vdso: use the right format for ABI
  docs: ABI: fix syntax to be parsed using ReST notation
  docs: ABI: convert testing/configfs-acpi to ReST
  docs: Kconfig/Makefile: add a check for broken ABI files
  docs: abi-testing.rst: enable --rst-sources when building docs
  docs: ABI: don't escape ReST-incompatible chars from obsolete and removed
  docs: ABI: create a 2-depth index for ABI
  docs: ABI: make it parse ABI/stable as ReST-compatible files
  docs: ABI: sysfs-uevent: make it compatible with ReST output
  docs: ABI: testing: make the files compatible with ReST output
  ...

Pull staging driver fixes from Greg KH:
 "Here are some small staging driver fixes for issues that have been
  reported in 5.10-rc1:

   - octeon driver fixes

   - wfx driver fixes

   - memory leak fix in vchiq driver

   - fieldbus driver bugfix

   - comedi driver bugfix

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

* tag 'staging-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: fieldbus: anybuss: jump to correct label in an error path
  staging: wfx: fix test on return value of gpiod_get_value()
  staging: wfx: fix use of uninitialized pointer
  staging: mmal-vchiq: Fix memory leak for vchiq_instance
  staging: comedi: cb_pcidas: Allow 2-channel commands for AO subdevice
  staging: octeon: Drop on uncorrectable alignment or FCS error
  staging: octeon: repair "fixed-link" support

Pull tty/serial fixes from Greg KH:
 "Here are some small TTY and Serial driver fixes for reported issues
  for 5.10-rc2. They include:

   - vt ioctl bugfix for reported problems

   - fsl_lpuart serial driver fix

   - 21285 serial driver bugfix

  All have been in linux-next with no reported issues"

* tag 'tty-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  vt_ioctl: fix GIO_UNIMAP regression
  vt: keyboard, extend func_buf_lock to readers
  vt: keyboard, simplify vt_kdgkbsent
  tty: serial: fsl_lpuart: LS1021A has a FIFO size of 16 words, like LS1028A
  tty: serial: 21285: fix lockup on open

Pull USB driver fixes from Greg KH:
 "Here are a number of small bugfixes for reported issues in some USB
  drivers. They include:

   - typec bugfixes

   - xhci bugfixes and lockdep warning fixes

   - cdc-acm driver regression fix

   - kernel doc fixes

   - cdns3 driver bugfixes for a bunch of reported issues

   - other tiny USB driver fixes

  All have been in linux-next with no reported issues"

* tag 'usb-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: cdns3: gadget: own the lock wrongly at the suspend routine
  usb: cdns3: Fix on-chip memory overflow issue
  usb: cdns3: gadget: suspicious implicit sign extension
  xhci: Don't create stream debugfs files with spinlock held.
  usb: xhci: Workaround for S3 issue on AMD SNPS 3.0 xHC
  xhci: Fix sizeof() mismatch
  usb: typec: stusb160x: fix signedness comparison issue with enum variables
  usb: typec: add missing MODULE_DEVICE_TABLE() to stusb160x
  USB: apple-mfi-fastcharge: don't probe unhandled devices
  usbcore: Check both id_table and match() when both available
  usb: host: ehci-tegra: Fix error handling in tegra_ehci_probe()
  usb: typec: stusb160x: fix an IS_ERR() vs NULL check in probe
  usb: typec: tcpm: reset hard_reset_count for any disconnect
  usb: cdc-acm: fix cooldown mechanism
  usb: host: fsl-mph-dr-of: check return of dma_set_mask()
  usb: fix kernel-doc markups
  usb: typec: stusb160x: fix some signedness bugs
  usb: cdns3: Variable 'length' set but not used

Pull kvm fixes from Paolo Bonzini:
 "ARM:
   - selftest fix
   - force PTE mapping on device pages provided via VFIO
   - fix detection of cacheable mapping at S2
   - fallback to PMD/PTE mappings for composite huge pages
   - fix accounting of Stage-2 PGD allocation
   - fix AArch32 handling of some of the debug registers
   - simplify host HYP entry
   - fix stray pointer conversion on nVHE TLB invalidation
   - fix initialization of the nVHE code
   - simplify handling of capabilities exposed to HYP
   - nuke VCPUs caught using a forbidden AArch32 EL0

  x86:
   - new nested virtualization selftest
   - miscellaneous fixes
   - make W=1 fixes
   - reserve new CPUID bit in the KVM leaves"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: vmx: remove unused variable
  KVM: selftests: Don't require THP to run tests
  KVM: VMX: eVMCS: make evmcs_sanitize_exec_ctrls() work again
  KVM: selftests: test behavior of unmapped L2 APIC-access address
  KVM: x86: Fix NULL dereference at kvm_msr_ignored_check()
  KVM: x86: replace static const variables with macros
  KVM: arm64: Handle Asymmetric AArch32 systems
  arm64: cpufeature: upgrade hyp caps to final
  arm64: cpufeature: reorder cpus_have_{const, final}_cap()
  KVM: arm64: Factor out is_{vhe,nvhe}_hyp_code()
  KVM: arm64: Force PTE mapping on fault resulting in a device mapping
  KVM: arm64: Use fallback mapping sizes for contiguous huge page sizes
  KVM: arm64: Fix masks in stage2_pte_cacheable()
  KVM: arm64: Fix AArch32 handling of DBGD{CCINT,SCRext} and DBGVCR
  KVM: arm64: Allocate stage-2 pgd pages with GFP_KERNEL_ACCOUNT
  KVM: arm64: Drop useless PAN setting on host EL1 to EL2 transition
  KVM: arm64: Remove leftover kern_hyp_va() in nVHE TLB invalidation
  KVM: arm64: Don't corrupt tpidr_el2 on failed HVC call
  x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID

Pull vhost fixes from Michael Tsirkin:
 "Fixes all over the place.

  A new UAPI is borderline: can also be considered a new feature but
  also seems to be the only way we could come up with to fix addressing
  for userspace - and it seems important to switch to it now before
  userspace making assumptions about addressing ability of devices is
  set in stone"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vdpasim: allow to assign a MAC address
  vdpasim: fix MAC address configuration
  vdpa: handle irq bypass register failure case
  vdpa_sim: Fix DMA mask
  Revert "vhost-vdpa: fix page pinning leakage in error path"
  vdpa/mlx5: Fix error return in map_direct_mr()
  vhost_vdpa: Return -EFAULT if copy_from_user() fails
  vdpa_sim: implement get_iova_range()
  vhost: vdpa: report iova range
  vdpa: introduce config op to get valid iova range

Merge tag 'flexible-array-conversions-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull more flexible-array member conversions from Gustavo A. R. Silva:
 "Replace zero-length arrays with flexible-array members"

* tag 'flexible-array-conversions-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  printk: ringbuffer: Replace zero-length array with flexible-array member
  net/smc: Replace zero-length array with flexible-array member
  net/mlx5: Replace zero-length array with flexible-array member
  mei: hw: Replace zero-length array with flexible-array member
  gve: Replace zero-length array with flexible-array member
  Bluetooth: btintel: Replace zero-length array with flexible-array member
  scsi: target: tcmu: Replace zero-length array with flexible-array member
  ima: Replace zero-length array with flexible-array member
  enetc: Replace zero-length array with flexible-array member
  fs: Replace zero-length array with flexible-array member
  Bluetooth: Replace zero-length array with flexible-array member
  params: Replace zero-length array with flexible-array member
  tracepoint: Replace zero-length array with flexible-array member
  platform/chrome: cros_ec_proto: Replace zero-length array with flexible-array member
  platform/chrome: cros_ec_commands: Replace zero-length array with flexible-array member
  mailbox: zynqmp-ipi-message: Replace zero-length array with flexible-array member
  dmaengine: ti-cppi5: Replace zero-length array with flexible-array member

Pull dma-mapping fix from Christoph Hellwig:
 "Fix an integer overflow on 32-bit platforms in the new DMA range code
  (Geert Uytterhoeven)"

* tag 'dma-mapping-5.10-2' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: fix 32-bit overflow with CONFIG_ARM_LPAE=n

Pull SCSI fixes from James Bottomley:
 "Four driver fixes and one core fix.

  The core fix closes a race window where we could kick off a second
  asynchronous scan because the test and set of the variable preventing
  it isn't atomic"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: hisi_sas: Stop using queue #0 always for v2 hw
  scsi: ibmvscsi: Fix potential race after loss of transport
  scsi: mptfusion: Fix null pointer dereferences in mptscsih_remove()
  scsi: qla2xxx: Return EBUSY on fcport deletion
  scsi: core: Don't start concurrent async scan on same host

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Unless we want to test with THP, then we shouldn't require it to be
configured by the host kernel. Unfortunately, even advising with
MADV_NOHUGEPAGE does require it, so check for THP first in order
to avoid madvise failing with EINVAL.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20201029201703.102716-2-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

It was noticed that evmcs_sanitize_exec_ctrls() is not being executed
nowadays despite the code checking 'enable_evmcs' static key looking
correct. Turns out, static key magic doesn't work in '__init' section
(and it is unclear when things changed) but setup_vmcs_config() is called
only once per CPU so we don't really need it to. Switch to checking
'enlightened_vmcs' instead, it is supposed to be in sync with
'enable_evmcs'.

Opportunistically make evmcs_sanitize_exec_ctrls '__init' and drop unneeded
extra newline from it.
Reported-by: Yang Weijiang <weijiang.yang@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201014143346.2430936-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a regression test for commit 671ddc70 ("KVM: nVMX: Don't leak
L1 MMIO regions to L2").

First, check to see that an L2 guest can be launched with a valid
APIC-access address that is backed by a page of L1 physical memory.

Next, set the APIC-access address to a (valid) L1 physical address
that is not backed by memory. KVM can't handle this situation, so
resuming L2 should result in a KVM exit for internal error
(emulation).
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Message-Id: <20201026180922.3120555-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull block fixes from Jens Axboe:

 - null_blk zone fixes (Damien, Kanchan)

 - NVMe pull request from Christoph:
       - improve zone revalidation (Keith Busch)
       - gracefully handle zero length messages in nvme-rdma (zhenwei pi)
       - nvme-fc error handling fixes (James Smart)
       - nvmet tracing NULL pointer dereference fix (Chaitanya Kulkarni)"

 - xsysace platform fixes (Andy)

 - scatterlist type cleanup (David)

 - blk-cgroup memory fixes (Gabriel)

 - nbd block size update fix (Ming)

 - Flush completion state fix (Ming)

 - bio_add_hw_page() iteration fix (Naohiro)

* tag 'block-5.10-2020-10-30' of git://git.kernel.dk/linux-block:
  blk-mq: mark flush request as IDLE in flush_end_io()
  lib/scatterlist: use consistent sg_copy_buffer() return type
  xsysace: use platform_get_resource() and platform_get_irq_optional()
  null_blk: Fix locking in zoned mode
  null_blk: Fix zone reset all tracing
  nbd: don't update block size after device is started
  block: advance iov_iter on bio_add_hw_page failure
  null_blk: synchronization fix for zoned device
  nvmet: fix a NULL pointer dereference when tracing the flush command
  nvme-fc: remove nvme_fc_terminate_io()
  nvme-fc: eliminate terminate_io use by nvme_fc_error_recovery
  nvme-fc: remove err_work work item
  nvme-fc: track error_recovery while connecting
  nvme-rdma: handle unexpected nvme completion data length
  nvme: ignore zone validate errors on subsequent scans
  blk-cgroup: Pre-allocate tree node on blkg_conf_prep
  blk-cgroup: Fix memleak on error path

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arraysSigned-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>