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, 112 insertions, 0 deletions

diff --git a/drivers/base/test/root-device-test.c b/drivers/base/test/root-device-test.c
new file mode 100644
index 000000000..9aea23c91
--- /dev/null
+++ b/drivers/base/test/root-device-test.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2023 Maxime Ripard <mripard@kernel.org>
+
+#include <kunit/resource.h>
+
+#include <linux/device.h>
+
+#define DEVICE_NAME "test"
+
+struct test_priv {
+	bool probe_done;
+	bool release_done;
+	wait_queue_head_t release_wq;
+	struct device *dev;
+};
+
+static int root_device_devm_init(struct kunit *test)
+{
+	struct test_priv *priv;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+	init_waitqueue_head(&priv->release_wq);
+
+	test->priv = priv;
+
+	return 0;
+}
+
+static void devm_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+#define RELEASE_TIMEOUT_MS	100
+
+/*
+ * Tests that a bus-less, non-probed device will run its device-managed
+ * actions when unregistered.
+ */
+static void root_device_devm_register_unregister_test(struct kunit *test)
+{
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	priv->dev = root_device_register(DEVICE_NAME);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	root_device_unregister(priv->dev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static void devm_put_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	put_device(priv->dev);
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+/*
+ * Tests that a bus-less, non-probed device will run its device-managed
+ * actions when unregistered, even if someone still holds a reference to
+ * it.
+ */
+static void root_device_devm_register_get_unregister_with_devm_test(struct kunit *test)
+{
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	priv->dev = root_device_register(DEVICE_NAME);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
+
+	get_device(priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	root_device_unregister(priv->dev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static struct kunit_case root_device_devm_tests[] = {
+	KUNIT_CASE(root_device_devm_register_unregister_test),
+	KUNIT_CASE(root_device_devm_register_get_unregister_with_devm_test),
+	{}
+};
+
+static struct kunit_suite root_device_devm_test_suite = {
+	.name = "root-device-devm",
+	.init = root_device_devm_init,
+	.test_cases = root_device_devm_tests,
+};
+
+kunit_test_suite(root_device_devm_test_suite);
+
+MODULE_DESCRIPTION("Test module for root devices");
+MODULE_AUTHOR("Maxime Ripard <mripard@kernel.org>");
+MODULE_LICENSE("GPL");