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, 82 insertions, 0 deletions

diff --git a/tools/perf/tests/mem2node.c b/tools/perf/tests/mem2node.c
new file mode 100644
index 000000000..7ce1ad7b6
--- /dev/null
+++ b/tools/perf/tests/mem2node.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/bitmap.h>
+#include <linux/kernel.h>
+#include <linux/zalloc.h>
+#include <perf/cpumap.h>
+#include <internal/cpumap.h>
+#include "debug.h"
+#include "env.h"
+#include "mem2node.h"
+#include "tests.h"
+
+static struct node {
+	int		 node;
+	const char 	*map;
+} test_nodes[] = {
+	{ .node = 0, .map = "0"     },
+	{ .node = 1, .map = "1-2"   },
+	{ .node = 3, .map = "5-7,9" },
+};
+
+#define T TEST_ASSERT_VAL
+
+static unsigned long *get_bitmap(const char *str, int nbits)
+{
+	struct perf_cpu_map *map = perf_cpu_map__new(str);
+	unsigned long *bm = NULL;
+
+	bm = bitmap_zalloc(nbits);
+
+	if (map && bm) {
+		struct perf_cpu cpu;
+		unsigned int i;
+
+		perf_cpu_map__for_each_cpu(cpu, i, map)
+			__set_bit(cpu.cpu, bm);
+	}
+
+	if (map)
+		perf_cpu_map__put(map);
+	else
+		free(bm);
+
+	return bm && map ? bm : NULL;
+}
+
+static int test__mem2node(struct test_suite *t __maybe_unused, int subtest __maybe_unused)
+{
+	struct mem2node map;
+	struct memory_node nodes[3];
+	struct perf_env env = {
+		.memory_nodes    = (struct memory_node *) &nodes[0],
+		.nr_memory_nodes = ARRAY_SIZE(nodes),
+		.memory_bsize    = 0x100,
+	};
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(nodes); i++) {
+		nodes[i].node = test_nodes[i].node;
+		nodes[i].size = 10;
+
+		T("failed: alloc bitmap",
+		  (nodes[i].set = get_bitmap(test_nodes[i].map, 10)));
+	}
+
+	T("failed: mem2node__init", !mem2node__init(&map, &env));
+	T("failed: mem2node__node",  0 == mem2node__node(&map,   0x50));
+	T("failed: mem2node__node",  1 == mem2node__node(&map,  0x100));
+	T("failed: mem2node__node",  1 == mem2node__node(&map,  0x250));
+	T("failed: mem2node__node",  3 == mem2node__node(&map,  0x500));
+	T("failed: mem2node__node",  3 == mem2node__node(&map,  0x650));
+	T("failed: mem2node__node", -1 == mem2node__node(&map,  0x450));
+	T("failed: mem2node__node", -1 == mem2node__node(&map, 0x1050));
+
+	for (i = 0; i < ARRAY_SIZE(nodes); i++)
+		zfree(&nodes[i].set);
+
+	mem2node__exit(&map);
+	return 0;
+}
+
+DEFINE_SUITE("mem2node", mem2node);