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, 25 insertions, 0 deletions

diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig
new file mode 100644
index 000000000..b0fe1cce3
--- /dev/null
+++ b/fs/sysfs/Kconfig
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SYSFS
+	bool "sysfs file system support" if EXPERT
+	default y
+	select KERNFS
+	help
+	The sysfs filesystem is a virtual filesystem that the kernel uses to
+	export internal kernel objects, their attributes, and their
+	relationships to one another.
+
+	Users can use sysfs to ascertain useful information about the running
+	kernel, such as the devices the kernel has discovered on each bus and
+	which driver each is bound to. sysfs can also be used to tune devices
+	and other kernel subsystems.
+
+	Some system agents rely on the information in sysfs to operate.
+	/sbin/hotplug uses device and object attributes in sysfs to assist in
+	delegating policy decisions, like persistently naming devices.
+
+	sysfs is currently used by the block subsystem to mount the root
+	partition.  If sysfs is disabled you must specify the boot device on
+	the kernel boot command line via its major and minor numbers.  For
+	example, "root=03:01" for /dev/hda1.
+
+	Designers of embedded systems may wish to say N here to conserve space.