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, 75 insertions, 0 deletions

diff --git a/scripts/package/install-extmod-build b/scripts/package/install-extmod-build
new file mode 100755
index 000000000..f12e1ffe4
--- /dev/null
+++ b/scripts/package/install-extmod-build
@@ -0,0 +1,75 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+set -eu
+
+destdir=${1}
+
+is_enabled() {
+	grep -q "^$1=y" include/config/auto.conf
+}
+
+find_in_scripts() {
+	find scripts \
+		\( -name atomic -o -name dtc -o -name kconfig -o -name package \) -prune -o \
+		! -name unifdef -a ! -name mk_elfconfig -a \( -type f -o -type l \) -print
+}
+
+mkdir -p "${destdir}"
+
+(
+	cd "${srctree}"
+	echo Makefile
+	find "arch/${SRCARCH}" -maxdepth 1 -name 'Makefile*'
+	find "arch/${SRCARCH}" -name generated -prune -o -name include -type d -print
+	find "arch/${SRCARCH}" -name Kbuild.platforms -o -name Platform
+	find include \( -name config -o -name generated \) -prune -o \( -type f -o -type l \) -print
+	find_in_scripts
+) | tar -c -f - -C "${srctree}" -T - | tar -xf - -C "${destdir}"
+
+{
+	if is_enabled CONFIG_OBJTOOL; then
+		echo tools/objtool/objtool
+	fi
+
+	if is_enabled CONFIG_DEBUG_INFO_BTF_MODULES; then
+		echo tools/bpf/resolve_btfids/resolve_btfids
+	fi
+
+	echo Module.symvers
+	echo "arch/${SRCARCH}/include/generated"
+	echo include/config/auto.conf
+	echo include/config/kernel.release
+	echo include/generated
+	find_in_scripts
+
+	if is_enabled CONFIG_GCC_PLUGINS; then
+		find scripts/gcc-plugins -name '*.so'
+	fi
+} | tar -c -f - -T - | tar -xf - -C "${destdir}"
+
+# When ${CC} and ${HOSTCC} differ, rebuild host programs using ${CC}.
+#
+# This caters to host programs that participate in Kbuild. objtool and
+# resolve_btfids are out of scope.
+if [ "${CC}" != "${HOSTCC}" ]; then
+	cat "${destdir}/scripts/Makefile" - <<-'EOF' > "${destdir}/scripts/Kbuild"
+	subdir-y += basic
+	hostprogs-always-y += mod/modpost
+	mod/modpost-objs := $(addprefix mod/, modpost.o file2alias.o sumversion.o symsearch.o)
+	EOF
+
+	# HOSTCXX is not overridden. The C++ compiler is used to build:
+	# - scripts/kconfig/qconf, which is unneeded for external module builds
+	# - GCC plugins, which will not work on the installed system even after
+	#   being rebuilt.
+	#
+	# Clear VPATH and srcroot because the source files reside in the output
+	# directory.
+	# shellcheck disable=SC2016 # $(MAKE) and $(build) will be expanded by Make
+	"${MAKE}" run-command KBUILD_RUN_COMMAND='+$(MAKE) HOSTCC="'"${CC}"'" VPATH= srcroot=. $(build)='"$(realpath --relative-to=. "${destdir}")"/scripts
+
+	rm -f "${destdir}/scripts/Kbuild"
+fi
+
+find "${destdir}" \( -name '.*.cmd' -o -name '*.o' \) -delete