Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU updates from Paul McKenney:

1. Miscellaneous fixes.
2. kfree_rcu() updates.

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU updates from Paul McKenney:

1. Miscellaneous fixes.
2. kfree_rcu() updates.
3. Remove scheduler locking restriction
4. RCU-tasks update, including addition of RCU Tasks Trace for
BPF use and RCU Tasks Rude. (This branch is on top of #3 due
to overlap of changed code.)
5. RCU CPU stall warning updates.
6. Torture-test updates.

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Merge branches 'fixes.2020.04.27a', 'kfree_rcu.2020.04.27a', 'rcu-tasks.2020.04.27a', 'stall.2020.04.27a' and 'torture.2020.05.07a' into HEAD

fixes.2020.04.27a: Miscellaneous fixes.
kfree_rcu.2020.

Merge branches 'fixes.2020.04.27a', 'kfree_rcu.2020.04.27a', 'rcu-tasks.2020.04.27a', 'stall.2020.04.27a' and 'torture.2020.05.07a' into HEAD

fixes.2020.04.27a: Miscellaneous fixes.
kfree_rcu.2020.04.27a: Changes related to kfree_rcu().
rcu-tasks.2020.04.27a: Addition of new RCU-tasks flavors.
stall.2020.04.27a: RCU CPU stall-warning updates.
torture.2020.05.07a: Torture-test updates.

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rcu-tasks: Allow rcu_read_unlock_trace() under scheduler locks

The rcu_read_unlock_trace() can invoke rcu_read_unlock_trace_special(),
which in turn can call wake_up(). Therefore, if any scheduler

rcu-tasks: Allow rcu_read_unlock_trace() under scheduler locks

The rcu_read_unlock_trace() can invoke rcu_read_unlock_trace_special(),
which in turn can call wake_up(). Therefore, if any scheduler lock is
held across a call to rcu_read_unlock_trace(), self-deadlock can occur.
This commit therefore uses the irq_work facility to defer the wake_up()
to a clean environment where no scheduler locks will be held.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
[ paulmck: Update #includes for m68k per kbuild test robot. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu-tasks: Move #ifdef into tasks.h

This commit pushes the #ifdef CONFIG_TASKS_RCU_GENERIC from
kernel/rcu/update.c to kernel/rcu/tasks.h in order to improve
readability as more APIs are added.

Sig

rcu-tasks: Move #ifdef into tasks.h

This commit pushes the #ifdef CONFIG_TASKS_RCU_GENERIC from
kernel/rcu/update.c to kernel/rcu/tasks.h in order to improve
readability as more APIs are added.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu-tasks: Refactor RCU-tasks to allow variants to be added

This commit splits out generic processing from RCU-tasks-specific
processing in order to allow additional flavors to be added. It also
ad

rcu-tasks: Refactor RCU-tasks to allow variants to be added

This commit splits out generic processing from RCU-tasks-specific
processing in order to allow additional flavors to be added. It also
adds a def_bool TASKS_RCU_GENERIC to enable the common RCU-tasks
infrastructure code.

This is primarily, but not entirely, a code-movement commit.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu-tasks: Move Tasks RCU to its own file

This code-movement-only commit is in preparation for adding an additional
flavor of Tasks RCU, which relies on workqueues to detect grace periods.

Signed-o

rcu-tasks: Move Tasks RCU to its own file

This code-movement-only commit is in preparation for adding an additional
flavor of Tasks RCU, which relies on workqueues to detect grace periods.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu: Add KCSAN stubs to update.c

This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros
to move ahead.

Sign

rcu: Add KCSAN stubs to update.c

This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros
to move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu: Replace assigned pointer ret value by corresponding boolean value

Coccinelle reports warnings at rcu_read_lock_held_common()

WARNING: Assignment of 0/1 to bool variable

To fix this,
the assig

rcu: Replace assigned pointer ret value by corresponding boolean value

Coccinelle reports warnings at rcu_read_lock_held_common()

WARNING: Assignment of 0/1 to bool variable

To fix this,
the assigned pointer ret values are replaced by corresponding boolean value.
Given that ret is a pointer of bool type

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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rcu: Get rid of some doc warnings in update.c

This commit escapes *ret, because otherwise the documentation system
thinks that this is an incomplete emphasis block:

./kernel/rcu/update.c:65: WARNI

rcu: Get rid of some doc warnings in update.c

This commit escapes *ret, because otherwise the documentation system
thinks that this is an incomplete emphasis block:

./kernel/rcu/update.c:65: WARNING: Inline emphasis start-string without end-string.
./kernel/rcu/update.c:65: WARNING: Inline emphasis start-string without end-string.
./kernel/rcu/update.c:70: WARNING: Inline emphasis start-string without end-string.
./kernel/rcu/update.c:82: WARNING: Inline emphasis start-string without end-string.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core

Pull EFI changes for v5.8 from Ard Biesheuvel:

"- preliminary changes for RISC-V
- add support for setti

Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core

Pull EFI changes for v5.8 from Ard Biesheuvel:

"- preliminary changes for RISC-V
- add support for setting the resolution on the EFI framebuffer
- simplify kernel image loading for arm64
- Move .bss into .data via the linker script instead of relying on symbol
annotations.
- Get rid of __pure getters to access global variables
- Clean up the config table matching arrays"

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'topic/nhlt' into for-next

Merge NHLT init cleanup.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Merge tag 'tegra-for-5.7-asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into asoc-5.7

ASoC: tegra: Fixes for v5.7-rc3

This contains a couple of fixes that are needed to properly

Merge tag 'tegra-for-5.7-asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into asoc-5.7

ASoC: tegra: Fixes for v5.7-rc3

This contains a couple of fixes that are needed to properly reconfigure
the audio clocks on older Tegra devices.

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Merge branch 'fixes-v5.7' into fixes

Merge drm/drm-next into drm-misc-next

Backmerging required to pull topic/phy-compliance.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-intel-next-queued

Backmerging in order to pull "topic/phy-compliance".

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge v5.7-rc1 into drm-misc-fixes

Start the new drm-misc-fixes cycle.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor "evil merge" to move the KCSAN entry up a

Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines
in the Kconfig to reduce the probability of future conflicts.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'for-5.7/appleir' into for-linus

- small code cleanups in hid-appleir from Lucas Tanure

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:

- Continued user-acce

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:

- Continued user-access cleanups in the futex code.

- percpu-rwsem rewrite that uses its own waitqueue and atomic_t
instead of an embedded rwsem. This addresses a couple of
weaknesses, but the primary motivation was complications on the -rt
kernel.

- Introduce raw lock nesting detection on lockdep
(CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal
lock differences. This too originates from -rt.

- Reuse lockdep zapped chain_hlocks entries, to conserve RAM
footprint on distro-ish kernels running into the "BUG:
MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep
chain-entries pool.

- Misc cleanups, smaller fixes and enhancements - see the changelog
for details"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t
thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t
Documentation/locking/locktypes: Minor copy editor fixes
Documentation/locking/locktypes: Further clarifications and wordsmithing
m68knommu: Remove mm.h include from uaccess_no.h
x86: get rid of user_atomic_cmpxchg_inatomic()
generic arch_futex_atomic_op_inuser() doesn't need access_ok()
x86: don't reload after cmpxchg in unsafe_atomic_op2() loop
x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end()
objtool: whitelist __sanitizer_cov_trace_switch()
[parisc, s390, sparc64] no need for access_ok() in futex handling
sh: no need of access_ok() in arch_futex_atomic_op_inuser()
futex: arch_futex_atomic_op_inuser() calling conventions change
completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all()
lockdep: Add posixtimer context tracing bits
lockdep: Annotate irq_work
lockdep: Add hrtimer context tracing bits
lockdep: Introduce wait-type checks
completion: Use simple wait queues
sched/swait: Prepare usage in completions
...

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Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
"The main changes in this cycle were:

- Make kfree_rcu() use kfree_

Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
"The main changes in this cycle were:

- Make kfree_rcu() use kfree_bulk() for added performance

- RCU updates

- Callback-overload handling updates

- Tasks-RCU KCSAN and sparse updates

- Locking torture test and RCU torture test updates

- Documentation updates

- Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
rcu: Make rcu_barrier() account for offline no-CBs CPUs
rcu: Mark rcu_state.gp_seq to detect concurrent writes
Documentation/memory-barriers: Fix typos
doc: Add rcutorture scripting to torture.txt
doc/RCU/rcu: Use https instead of http if possible
doc/RCU/rcu: Use absolute paths for non-rst files
doc/RCU/rcu: Use ':ref:' for links to other docs
doc/RCU/listRCU: Update example function name
doc/RCU/listRCU: Fix typos in a example code snippets
doc/RCU/Design: Remove remaining HTML tags in ReST files
doc: Add some more RCU list patterns in the kernel
rcutorture: Set KCSAN Kconfig options to detect more data races
rcutorture: Manually clean up after rcu_barrier() failure
rcutorture: Make rcu_torture_barrier_cbs() post from corresponding CPU
rcuperf: Measure memory footprint during kfree_rcu() test
rcutorture: Annotation lockless accesses to rcu_torture_current
rcutorture: Add READ_ONCE() to rcu_torture_count and rcu_torture_batch
rcutorture: Fix stray access to rcu_fwd_cb_nodelay
rcutorture: Fix rcu_torture_one_read()/rcu_torture_writer() data race
rcutorture: Make kvm-find-errors.sh abort on bad directory
...

show more ...

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU changes from Paul E. McKenney:

- Make kfree_rcu() use kfree_bulk() for added perf

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU changes from Paul E. McKenney:

- Make kfree_rcu() use kfree_bulk() for added performance
- RCU updates
- Callback-overload handling updates
- Tasks-RCU KCSAN and sparse updates
- Locking torture test and RCU torture test updates
- Documentation updates
- Miscellaneous fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

show more ...

Merge branches 'doc.2020.02.27a', 'fixes.2020.03.21a', 'kfree_rcu.2020.02.20a', 'locktorture.2020.02.20a', 'ovld.2020.02.20a', 'rcu-tasks.2020.02.20a', 'srcu.2020.02.20a' and 'torture.2020.02.20a' in

Merge branches 'doc.2020.02.27a', 'fixes.2020.03.21a', 'kfree_rcu.2020.02.20a', 'locktorture.2020.02.20a', 'ovld.2020.02.20a', 'rcu-tasks.2020.02.20a', 'srcu.2020.02.20a' and 'torture.2020.02.20a' into HEAD

doc.2020.02.27a: Documentation updates.
fixes.2020.03.21a: Miscellaneous fixes.
kfree_rcu.2020.02.20a: Updates to kfree_rcu().
locktorture.2020.02.20a: Lock torture-test updates.
ovld.2020.02.20a: Updates to callback-overload handling.
rcu-tasks.2020.02.20a: RCU-tasks updates.
srcu.2020.02.20a: SRCU updates.
torture.2020.02.20a: Torture-test updates.

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lockdep: Introduce wait-type checks

Extend lockdep to validate lock wait-type context.

The current wait-types are:

LD_WAIT_FREE, /* wait free, rcu etc.. */
LD_WAIT_SPIN, /* spin loops, raw_spi

lockdep: Introduce wait-type checks

Extend lockdep to validate lock wait-type context.

The current wait-types are:

LD_WAIT_FREE, /* wait free, rcu etc.. */
LD_WAIT_SPIN, /* spin loops, raw_spinlock_t etc.. */
LD_WAIT_CONFIG, /* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
LD_WAIT_SLEEP, /* sleeping locks, mutex_t etc.. */

Where lockdep validates that the current lock (the one being acquired)
fits in the current wait-context (as generated by the held stack).

This ensures that there is no attempt to acquire mutexes while holding
spinlocks, to acquire spinlocks while holding raw_spinlocks and so on. In
other words, its a more fancy might_sleep().

Obviously RCU made the entire ordeal more complex than a simple single
value test because RCU can be acquired in (pretty much) any context and
while it presents a context to nested locks it is not the same as it
got acquired in.

Therefore its necessary to split the wait_type into two values, one
representing the acquire (outer) and one representing the nested context
(inner). For most 'normal' locks these two are the same.

[ To make static initialization easier we have the rule that:
.outer == INV means .outer == .inner; because INV == 0. ]

It further means that its required to find the minimal .inner of the held
stack to compare against the outer of the new lock; because while 'normal'
RCU presents a CONFIG type to nested locks, if it is taken while already
holding a SPIN type it obviously doesn't relax the rules.

Below is an example output generated by the trivial test code:

raw_spin_lock(&foo);
spin_lock(&bar);
spin_unlock(&bar);
raw_spin_unlock(&foo);

[ BUG: Invalid wait context ]
-----------------------------
swapper/0/1 is trying to lock:
ffffc90000013f20 (&bar){....}-{3:3}, at: kernel_init+0xdb/0x187
other info that might help us debug this:
1 lock held by swapper/0/1:
#0: ffffc90000013ee0 (&foo){+.+.}-{2:2}, at: kernel_init+0xd1/0x187

The way to read it is to look at the new -{n,m} part in the lock
description; -{3:3} for the attempted lock, and try and match that up to
the held locks, which in this case is the one: -{2,2}.

This tells that the acquiring lock requires a more relaxed environment than
presented by the lock stack.

Currently only the normal locks and RCU are converted, the rest of the
lockdep users defaults to .inner = INV which is ignored. More conversions
can be done when desired.

The check for spinlock_t nesting is not enabled by default. It's a separate
config option for now as there are known problems which are currently
addressed. The config option allows to identify these problems and to
verify that the solutions found are indeed solving them.

The config switch will be removed and the checks will permanently enabled
once the vast majority of issues has been addressed.

[ bigeasy: Move LD_WAIT_FREE,… out of CONFIG_LOCKDEP to avoid compile
failure with CONFIG_DEBUG_SPINLOCK + !CONFIG_LOCKDEP]
[ tglx: Add the config option ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.427089655@linutronix.de

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Merge branch 'x86/kdump' into locking/kcsan, to resolve conflicts

Conflicts:
arch/x86/purgatory/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently lan

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently landed on drm-next.

Reference: https://patchwork.freedesktop.org/series/70952/
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com

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