Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

1 files changed, 40 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-kernel-reboot b/Documentation/ABI/testing/sysfs-kernel-reboot
new file mode 100644
index 000000000..52571fd5d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-reboot
@@ -0,0 +1,40 @@
+What:		/sys/kernel/reboot
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <teknoraver@meta.com>
+Description:	Interface to set the kernel reboot behavior, similarly to
+		what can be done via the reboot= cmdline option.
+		(see Documentation/admin-guide/kernel-parameters.txt)
+
+What:		/sys/kernel/reboot/mode
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <teknoraver@meta.com>
+Description:	Reboot mode. Valid values are: cold warm hard soft gpio
+
+What:		/sys/kernel/reboot/type
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <teknoraver@meta.com>
+Description:	Reboot type. Valid values are: bios acpi kbd triple efi pci
+
+What:		/sys/kernel/reboot/cpu
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <teknoraver@meta.com>
+Description:	CPU number to use to reboot.
+
+What:		/sys/kernel/reboot/force
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <teknoraver@meta.com>
+Description:	Don't wait for any other CPUs on reboot and
+		avoid anything that could hang.
+
+What:		/sys/kernel/reboot/hw_protection
+Date:		April 2025
+KernelVersion:	6.15
+Contact:	Ahmad Fatoum <a.fatoum@pengutronix.de>
+Description:	Hardware protection action taken on critical events like
+		overtemperature or imminent voltage loss.
+		Valid values are: reboot shutdown