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, 130 insertions, 0 deletions

diff --git a/lib/crc/Kconfig b/lib/crc/Kconfig
new file mode 100644
index 000000000..927fc6a6b
--- /dev/null
+++ b/lib/crc/Kconfig
@@ -0,0 +1,130 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Kconfig for the kernel's cyclic redundancy check (CRC) library code
+
+config CRC4
+	tristate
+	help
+	  The CRC4 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc4.h>.
+
+config CRC7
+	tristate
+	help
+	  The CRC7 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc7.h>.
+
+config CRC8
+	tristate
+	help
+	  The CRC8 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc8.h>.
+
+config CRC16
+	tristate
+	help
+	  The CRC16 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc16.h>.
+
+config CRC_CCITT
+	tristate
+	help
+	  The CRC-CCITT library functions.  Select this if your module uses any
+	  of the functions from <linux/crc-ccitt.h>.
+
+config CRC_ITU_T
+	tristate
+	help
+	  The CRC-ITU-T library functions.  Select this if your module uses
+	  any of the functions from <linux/crc-itu-t.h>.
+
+config CRC_T10DIF
+	tristate
+	help
+	  The CRC-T10DIF library functions.  Select this if your module uses
+	  any of the functions from <linux/crc-t10dif.h>.
+
+config CRC_T10DIF_ARCH
+	bool
+	depends on CRC_T10DIF && CRC_OPTIMIZATIONS
+	default y if ARM && KERNEL_MODE_NEON
+	default y if ARM64
+	default y if PPC64 && ALTIVEC
+	default y if RISCV && RISCV_ISA_ZBC
+	default y if X86
+
+config CRC32
+	tristate
+	select BITREVERSE
+	help
+	  The CRC32 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc32.h> or <linux/crc32c.h>.
+
+config CRC32_ARCH
+	bool
+	depends on CRC32 && CRC_OPTIMIZATIONS
+	default y if ARM && KERNEL_MODE_NEON
+	default y if ARM64
+	default y if LOONGARCH && 64BIT
+	default y if MIPS && CPU_MIPSR6
+	default y if PPC64 && ALTIVEC
+	default y if RISCV && RISCV_ISA_ZBC
+	default y if S390
+	default y if SPARC64
+	default y if X86
+
+config CRC64
+	tristate
+	help
+	  The CRC64 library functions.  Select this if your module uses any of
+	  the functions from <linux/crc64.h>.
+
+config CRC64_ARCH
+	bool
+	depends on CRC64 && CRC_OPTIMIZATIONS
+	default y if ARM && KERNEL_MODE_NEON && !CPU_BIG_ENDIAN
+	default y if ARM64
+	default y if RISCV && RISCV_ISA_ZBC && 64BIT
+	default y if X86_64
+
+config CRC_OPTIMIZATIONS
+	bool "Enable optimized CRC implementations" if EXPERT
+	depends on !UML
+	default y
+	help
+	  Disabling this option reduces code size slightly by disabling the
+	  architecture-optimized implementations of any CRC variants that are
+	  enabled.  CRC checksumming performance may get much slower.
+
+	  Keep this enabled unless you're really trying to minimize the size of
+	  the kernel.
+
+config CRC_KUNIT_TEST
+	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT && (CRC7 || CRC16 || CRC_T10DIF || CRC32 || CRC64)
+	default KUNIT_ALL_TESTS
+	help
+	  Unit tests for the CRC library functions.
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config CRC_ENABLE_ALL_FOR_KUNIT
+	tristate "Enable all CRC functions for KUnit test"
+	depends on KUNIT
+	select CRC7
+	select CRC16
+	select CRC_T10DIF
+	select CRC32
+	select CRC64
+	help
+	  Enable all CRC functions that have test code in CRC_KUNIT_TEST.
+
+	  Enable this only if you'd like the CRC KUnit test suite to test all
+	  the CRC variants, even ones that wouldn't otherwise need to be built.
+
+config CRC_BENCHMARK
+	bool "Benchmark for the CRC functions"
+	depends on CRC_KUNIT_TEST
+	help
+	  Include benchmarks in the KUnit test suite for the CRC functions.