Merge tag 'v6.6.6' into dev-6.6

This is the 6.6.6 stable release

Signed-off-by: Joel Stanley <joel@jms.id.au>

rcutorture: Fix stuttering races and other issues

[ Upstream commit cca42bd8eb1b54a4c9bbf48c79d120e66619a3e4 ]

The stuttering code isn't functioning as expected. Ideally, it should
pause the tortur

rcutorture: Fix stuttering races and other issues

[ Upstream commit cca42bd8eb1b54a4c9bbf48c79d120e66619a3e4 ]

The stuttering code isn't functioning as expected. Ideally, it should
pause the torture threads for a designated period before resuming. Yet,
it fails to halt the test for the correct duration. Additionally, a race
condition exists, potentially causing the stuttering code to pause for
an extended period if the 'spt' variable is non-zero due to the stutter
orchestration thread's inadequate CPU time.

Moreover, over-stuttering can hinder RCU's progress on TREE07 kernels.
This happens as the stuttering code may run within a softirq due to RCU
callbacks. Consequently, ksoftirqd keeps a CPU busy for several seconds,
thus obstructing RCU's progress. This situation triggers a warning
message in the logs:

[ 2169.481783] rcu_torture_writer: rtort_pipe_count: 9

This warning suggests that an RCU torture object, although invisible to
RCU readers, couldn't make it past the pipe array and be freed -- a
strong indication that there weren't enough grace periods during the
stutter interval.

To address these issues, this patch sets the "stutter end" time to an
absolute point in the future set by the main stutter thread. This is
then used for waiting in stutter_wait(). While the stutter thread still
defines this absolute time, the waiters' waiting logic doesn't rely on
the stutter thread receiving sufficient CPU time to halt the stuttering
as the halting is now self-controlled.

Cc: stable@vger.kernel.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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torture: Make torture_hrtimeout_ns() take an hrtimer mode parameter

[ Upstream commit a741deac787f0d2d7068638c067db20af9e63752 ]

The current torture-test sleeps are waiting for a duration, but ther

torture: Make torture_hrtimeout_ns() take an hrtimer mode parameter

[ Upstream commit a741deac787f0d2d7068638c067db20af9e63752 ]

The current torture-test sleeps are waiting for a duration, but there
are situations where it is better to wait for an absolute time, for
example, when ending a stutter interval. This commit therefore adds
an hrtimer mode parameter to torture_hrtimeout_ns(). Why not also the
other torture_hrtimeout_*() functions? The theory is that most absolute
times will be in nanoseconds, especially not (say) jiffies.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Stable-dep-of: cca42bd8eb1b ("rcutorture: Fix stuttering races and other issues")
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Merge drm/drm-fixes into drm-misc-fixes

Forwarding to v6.6-rc1.

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

Merge tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

- Documentation updates

- Miscellaneous fixes, perhaps most no

Merge tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

- Documentation updates

- Miscellaneous fixes, perhaps most notably simplifying
SRCU_NOTIFIER_INIT() as suggested

- RCU Tasks updates, most notably treating Tasks RCU callbacks as lazy
while still treating synchronous grace periods as urgent. Also fixes
one bug that restores the ability to apply debug-objects to RCU Tasks
and another that fixes a race condition that could result in
false-positive failures of the boot-time self-test code

- RCU-scalability performance-test updates, most notably adding the
ability to measure the RCU-Tasks's grace-period kthread's CPU
consumption. This proved quite useful for the RCU Tasks work

- Reference-acquisition/release performance-test updates, including a
fix for an uninitialized wait_queue_head_t

- Miscellaneous torture-test updates

- Torture-test scripting updates, including removal of the
non-longer-functional formal-verification scripts, test builds of
individual RCU Tasks flavors, better diagnostics for loss of
connectivity for distributed rcutorture tests, disabling of reboot
loops in qemu/KVM-based rcutorture testing, and passing of init
parameters to rcutorture's init program

* tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (64 commits)
rcu: Use WRITE_ONCE() for assignments to ->next for rculist_nulls
rcu: Make the rcu_nocb_poll boot parameter usable via boot config
rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load
srcu,notifier: Remove #ifdefs in favor of SRCU Tiny srcu_usage
rcutorture: Stop right-shifting torture_random() return values
torture: Stop right-shifting torture_random() return values
torture: Move stutter_wait() timeouts to hrtimers
torture: Move torture_shuffle() timeouts to hrtimers
torture: Move torture_onoff() timeouts to hrtimers
torture: Make torture_hrtimeout_*() use TASK_IDLE
torture: Add lock_torture writer_fifo module parameter
torture: Add a kthread-creation callback to _torture_create_kthread()
rcu-tasks: Fix boot-time RCU tasks debug-only deadlock
rcu-tasks: Permit use of debug-objects with RCU Tasks flavors
checkpatch: Complain about unexpected uses of RCU Tasks Trace
torture: Cause mkinitrd.sh to indicate failure on compile errors
torture: Make init program dump command-line arguments
torture: Switch qemu from -nographic to -display none
torture: Add init-program support for loongarch
torture: Avoid torture-test reboot loops
...

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Merge branches 'doc.2023.07.14b', 'fixes.2023.08.16a', 'rcu-tasks.2023.07.24a', 'rcuscale.2023.07.14b', 'refscale.2023.07.14b', 'torture.2023.08.14a' and 'torturescripts.2023.07.20a' into HEAD

doc.2

Merge branches 'doc.2023.07.14b', 'fixes.2023.08.16a', 'rcu-tasks.2023.07.24a', 'rcuscale.2023.07.14b', 'refscale.2023.07.14b', 'torture.2023.08.14a' and 'torturescripts.2023.07.20a' into HEAD

doc.2023.07.14b: Documentation updates.
fixes.2023.08.16a: Miscellaneous fixes.
rcu-tasks.2023.07.24a: RCU Tasks updates.
rcuscale.2023.07.14b: RCU (updater) scalability test updates.
refscale.2023.07.14b: Reference (reader) scalability test updates.
torture.2023.08.14a: Other torture-test updates.
torturescripts.2023.07.20a: Other torture-test scripting updates.

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torture: Stop right-shifting torture_random() return values

Now that torture_random() uses swahw32(), its callers no longer see
not-so-random low-order bits, as these are now swapped up into the upp

torture: Stop right-shifting torture_random() return values

Now that torture_random() uses swahw32(), its callers no longer see
not-so-random low-order bits, as these are now swapped up into the upper
16 bits of the torture_random() function's return value. This commit
therefore removes the right-shifting of torture_random() return values.

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

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torture: Move stutter_wait() timeouts to hrtimers

In order to gain better race coverage, move the test start/stop
waits in stutter_wait() to torture_hrtimeout_jiffies().

Signed-off-by: Paul E. McKe

torture: Move stutter_wait() timeouts to hrtimers

In order to gain better race coverage, move the test start/stop
waits in stutter_wait() to torture_hrtimeout_jiffies().

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

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torture: Move torture_shuffle() timeouts to hrtimers

In order to gain better race coverage, move the CPU-migration timed
waits in torture_shuffle() to torture_hrtimeout_jiffies().

Signed-off-by: Pa

torture: Move torture_shuffle() timeouts to hrtimers

In order to gain better race coverage, move the CPU-migration timed
waits in torture_shuffle() to torture_hrtimeout_jiffies().

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

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torture: Move torture_onoff() timeouts to hrtimers

In order to gain better race coverage, move the CPU-hotplug-related
timed waits in torture_onoff() to torture_hrtimeout_jiffies().

Signed-off-by:

torture: Move torture_onoff() timeouts to hrtimers

In order to gain better race coverage, move the CPU-hotplug-related
timed waits in torture_onoff() to torture_hrtimeout_jiffies().

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

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torture: Make torture_hrtimeout_*() use TASK_IDLE

Given that it is expected that more code will use torture_hrtimeout_*(),
including for longer timeouts, make it use TASK_IDLE instead of
TASK_UNINTE

torture: Make torture_hrtimeout_*() use TASK_IDLE

Given that it is expected that more code will use torture_hrtimeout_*(),
including for longer timeouts, make it use TASK_IDLE instead of
TASK_UNINTERRUPTIBLE.

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

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torture: Add lock_torture writer_fifo module parameter

This commit adds a module parameter that causes the locktorture writer
to run at real-time priority.

To use it:
insmod /lib/modules/torture.ko

torture: Add lock_torture writer_fifo module parameter

This commit adds a module parameter that causes the locktorture writer
to run at real-time priority.

To use it:
insmod /lib/modules/torture.ko random_shuffle=1
insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1
^^^^^^^^^^^^^

A predecessor to this patch has been helpful to uncover issues with the
proxy-execution series.

[ paulmck: Remove locktorture-specific code from kernel/torture.c. ]

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: kernel-team@android.com
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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torture: Add a kthread-creation callback to _torture_create_kthread()

This commit adds a kthread-creation callback to the
_torture_create_kthread() function, which allows callers of a new
torture_cr

torture: Add a kthread-creation callback to _torture_create_kthread()

This commit adds a kthread-creation callback to the
_torture_create_kthread() function, which allows callers of a new
torture_create_kthread_cb() macro to specify a function to be invoked
after the kthread is created but before it is awakened for the first time.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: John Stultz <jstultz@google.com>

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torture: Support randomized shuffling for proxy exec testing

Currently shuffling sets the same cpu affinities for all tasks,
which makes us less likely to hit paths involving migrating
blocked tasks

torture: Support randomized shuffling for proxy exec testing

Currently shuffling sets the same cpu affinities for all tasks,
which makes us less likely to hit paths involving migrating
blocked tasks onto a cpu where they can't run.

This patch adds an element of randomness to allow affinities of
different writer tasks to diverge.

This has helped uncover issues in testing with Proxy Execution

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
Signed-off-by: Connor O'Brien <connoro@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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Merge branch 'next' into for-linus

Prepare input updates for 6.4 merge window.

Merge drm/drm-next into drm-intel-gt-next

Need to pull in commit from drm-next (earlier in drm-intel-next):

1eca0778f4b3 ("drm/i915: add struct i915_dsm to wrap dsm members together")

In order to

Merge drm/drm-next into drm-intel-gt-next

Need to pull in commit from drm-next (earlier in drm-intel-next):

1eca0778f4b3 ("drm/i915: add struct i915_dsm to wrap dsm members together")

In order to merge following patch to drm-intel-gt-next:

https://patchwork.freedesktop.org/patch/530942/?series=114925&rev=6

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

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

Catch up with 6.3-rc cycle...

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge remote-tracking branch 'drm/drm-next' into msm-next

Merge drm-next into msm-next to pick up external clk and PM dependencies
for improved a6xx GPU reset sequence.

Signed-off-by: Rob Clark <ro

Merge remote-tracking branch 'drm/drm-next' into msm-next

Merge drm-next into msm-next to pick up external clk and PM dependencies
for improved a6xx GPU reset sequence.

Signed-off-by: Rob Clark <robdclark@chromium.org>

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Merge tag 'v6.3-rc2' into next

Merge with mainline to get of_property_present() and other newer APIs.

Merge drm/drm-fixes into drm-misc-fixes

Backmerging to get latest upstream.

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

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

Backmerging to get v6.3-rc1 and sync with the other DRM trees.

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

Merge remote-tracking branch 'acme/perf-tools' into perf-tools-next

To pick up perf-tools fixes just merged upstream.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge branch 'linus' into objtool/core, to pick up Xen dependencies

Pick up dependencies - freshly merged upstream via xen-next - before applying
dependent objtool changes.

Signed-off-by: Ingo Moln

Merge branch 'linus' into objtool/core, to pick up Xen dependencies

Pick up dependencies - freshly merged upstream via xen-next - before applying
dependent objtool changes.

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

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Merge tag 'rcu.2023.02.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

- Documentation updates

- Miscellaneous fixes, perhaps most no

Merge tag 'rcu.2023.02.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

- Documentation updates

- Miscellaneous fixes, perhaps most notably:

- Throttling callback invocation based on the number of callbacks
that are now ready to invoke instead of on the total number of
callbacks

- Several patches that suppress false-positive boot-time
diagnostics, for example, due to lockdep not yet being
initialized

- Make expedited RCU CPU stall warnings dump stacks of any tasks
that are blocking the stalled grace period. (Normal RCU CPU
stall warnings have done this for many years)

- Lazy-callback fixes to avoid delays during boot, suspend, and
resume. (Note that lazy callbacks must be explicitly enabled, so
this should not (yet) affect production use cases)

- Make kfree_rcu() and friends take advantage of polled grace periods,
thus reducing memory footprint by almost two orders of magnitude,
admittedly on a microbenchmark

This also begins the transition from kfree_rcu(p) to
kfree_rcu_mightsleep(p). This transition was motivated by bugs where
kfree_rcu(p), which can block, was typed instead of the intended
kfree_rcu(p, rh)

- SRCU updates, perhaps most notably fixing a bug that causes SRCU to
fail when booted on a system with a non-zero boot CPU. This
surprising situation actually happens for kdump kernels on the
powerpc architecture

This also adds an srcu_down_read() and srcu_up_read(), which act like
srcu_read_lock() and srcu_read_unlock(), but allow an SRCU read-side
critical section to be handed off from one task to another

- Clean up the now-useless SRCU Kconfig option

There are a few more commits that are not yet acked or pulled into
maintainer trees, and these will be in a pull request for a later
merge window

- RCU-tasks updates, perhaps most notably these fixes:

- A strange interaction between PID-namespace unshare and the
RCU-tasks grace period that results in a low-probability but
very real hang

- A race between an RCU tasks rude grace period on a single-CPU
system and CPU-hotplug addition of the second CPU that can
result in a too-short grace period

- A race between shrinking RCU tasks down to a single callback
list and queuing a new callback to some other CPU, but where
that queuing is delayed for more than an RCU grace period. This
can result in that callback being stranded on the non-boot CPU

- Torture-test updates and fixes

- Torture-test scripting updates and fixes

- Provide additional RCU CPU stall-warning information in kernels built
with CONFIG_RCU_CPU_STALL_CPUTIME=y, and restore the full five-minute
timeout limit for expedited RCU CPU stall warnings

* tag 'rcu.2023.02.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (80 commits)
rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()
kernel/notifier: Remove CONFIG_SRCU
init: Remove "select SRCU"
fs/quota: Remove "select SRCU"
fs/notify: Remove "select SRCU"
fs/btrfs: Remove "select SRCU"
fs: Remove CONFIG_SRCU
drivers/pci/controller: Remove "select SRCU"
drivers/net: Remove "select SRCU"
drivers/md: Remove "select SRCU"
drivers/hwtracing/stm: Remove "select SRCU"
drivers/dax: Remove "select SRCU"
drivers/base: Remove CONFIG_SRCU
rcu: Disable laziness if lazy-tracking says so
rcu: Track laziness during boot and suspend
rcu: Remove redundant call to rcu_boost_kthread_setaffinity()
rcu: Allow up to five minutes expedited RCU CPU stall-warning timeouts
rcu: Align the output of RCU CPU stall warning messages
rcu: Add RCU stall diagnosis information
sched: Add helper nr_context_switches_cpu()
...

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Merge branches 'doc.2023.01.05a', 'fixes.2023.01.23a', 'kvfree.2023.01.03a', 'srcu.2023.01.03a', 'srcu-always.2023.02.02a', 'tasks.2023.01.03a', 'torture.2023.01.05a' and 'torturescript.2023.01.03a'

Merge branches 'doc.2023.01.05a', 'fixes.2023.01.23a', 'kvfree.2023.01.03a', 'srcu.2023.01.03a', 'srcu-always.2023.02.02a', 'tasks.2023.01.03a', 'torture.2023.01.05a' and 'torturescript.2023.01.03a' into HEAD

doc.2023.01.05a: Documentation update.
fixes.2023.01.23a: Miscellaneous fixes.
kvfree.2023.01.03a: kvfree_rcu() updates.
srcu.2023.01.03a: SRCU updates.
srcu-always.2023.02.02a: Finish making SRCU be unconditionally available.
tasks.2023.01.03a: Tasks-RCU updates.
torture.2023.01.05a: Torture-test updates.
torturescript.2023.01.03a: Torture-test scripting updates.

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