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.

4 files changed, 82 insertions, 0 deletions

diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
new file mode 100644
index 000000000..bccc2c771
--- /dev/null
+++ b/tools/testing/kunit/configs/all_tests.config
@@ -0,0 +1,61 @@
+# This config enables as many tests as possible under UML.
+# It is intended for use in continuous integration systems and similar for
+# automated testing of as much as possible.
+# The config is manually maintained, though it uses KUNIT_ALL_TESTS=y to enable
+# any tests whose dependencies are already satisfied. Please feel free to add
+# more options if they any new tests.
+
+CONFIG_KUNIT=y
+CONFIG_KUNIT_EXAMPLE_TEST=y
+CONFIG_KUNIT_ALL_TESTS=y
+
+CONFIG_FORTIFY_SOURCE=y
+
+CONFIG_IIO=y
+
+CONFIG_EXT4_FS=y
+
+CONFIG_MSDOS_FS=y
+CONFIG_VFAT_FS=y
+
+CONFIG_PCI=y
+CONFIG_USB4=y
+CONFIG_I2C=y
+
+CONFIG_NET=y
+CONFIG_MCTP=y
+CONFIG_MCTP_FLOWS=y
+
+CONFIG_INET=y
+CONFIG_MPTCP=y
+
+CONFIG_NETDEVICES=y
+CONFIG_WLAN=y
+CONFIG_CFG80211=y
+CONFIG_MAC80211=y
+CONFIG_WLAN_VENDOR_INTEL=y
+CONFIG_IWLWIFI=y
+
+CONFIG_DAMON=y
+CONFIG_DAMON_VADDR=y
+CONFIG_DAMON_PADDR=y
+
+CONFIG_REGMAP_BUILD=y
+
+CONFIG_AUDIT=y
+
+CONFIG_CRYPTO_LIB_ENABLE_ALL_FOR_KUNIT=y
+
+CONFIG_PRIME_NUMBERS=y
+
+CONFIG_CRC_ENABLE_ALL_FOR_KUNIT=y
+
+CONFIG_SECURITY=y
+CONFIG_SECURITY_APPARMOR=y
+CONFIG_SECURITY_LANDLOCK=y
+
+CONFIG_SOUND=y
+CONFIG_SND=y
+CONFIG_SND_SOC=y
+CONFIG_SND_SOC_TOPOLOGY_BUILD=y
+CONFIG_SND_SOC_CS35L56_I2C=y
diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config
new file mode 100644
index 000000000..28edf816a
--- /dev/null
+++ b/tools/testing/kunit/configs/arch_uml.config
@@ -0,0 +1,7 @@
+# Config options which are added to UML builds by default
+
+# Enable pci, as a lot of tests require it.
+CONFIG_KUNIT_UML_PCI=y
+
+# Enable FORTIFY_SOURCE for wider checking.
+CONFIG_FORTIFY_SOURCE=y
diff --git a/tools/testing/kunit/configs/coverage_uml.config b/tools/testing/kunit/configs/coverage_uml.config
new file mode 100644
index 000000000..bacb77664
--- /dev/null
+++ b/tools/testing/kunit/configs/coverage_uml.config
@@ -0,0 +1,11 @@
+# This config fragment enables coverage on UML, which is different from the
+# normal gcov used in other arches (no debugfs).
+# Example usage:
+# ./tools/testing/kunit/kunit.py run \
+#   --kunitconfig=tools/testing/kunit/configs/all_tests_uml.config \
+#   --kunitconfig=tools/testing/kunit/configs/coverage_uml.config
+
+CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_GCOV=y
diff --git a/tools/testing/kunit/configs/default.config b/tools/testing/kunit/configs/default.config
new file mode 100644
index 000000000..e67af7b9f
--- /dev/null
+++ b/tools/testing/kunit/configs/default.config
@@ -0,0 +1,3 @@
+CONFIG_KUNIT=y
+CONFIG_KUNIT_EXAMPLE_TEST=y
+CONFIG_KUNIT_ALL_TESTS=y