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, 58 insertions, 0 deletions

diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h
new file mode 100644
index 000000000..7b1bda228
--- /dev/null
+++ b/tools/perf/util/cgroup.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CGROUP_H__
+#define __CGROUP_H__
+
+#include <linux/compiler.h>
+#include <linux/refcount.h>
+#include <linux/rbtree.h>
+#include "util/env.h"
+
+struct option;
+
+struct cgroup {
+	struct rb_node		node;
+	u64			id;
+	char			*name;
+	int			fd;
+	refcount_t		refcnt;
+};
+
+extern int nr_cgroups; /* number of explicit cgroups defined */
+extern bool cgrp_event_expanded;
+
+struct cgroup *cgroup__get(struct cgroup *cgroup);
+void cgroup__put(struct cgroup *cgroup);
+
+struct evlist;
+struct rblist;
+
+struct cgroup *cgroup__new(const char *name, bool do_open);
+struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name);
+int evlist__expand_cgroup(struct evlist *evlist, const char *cgroups, bool open_cgroup);
+
+void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup);
+
+int parse_cgroups(const struct option *opt, const char *str, int unset);
+
+struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
+			       const char *path);
+struct cgroup *cgroup__find(struct perf_env *env, uint64_t id);
+struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id);
+
+void perf_env__purge_cgroups(struct perf_env *env);
+
+#ifdef HAVE_FILE_HANDLE
+int read_cgroup_id(struct cgroup *cgrp);
+#else
+static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused)
+{
+	return -1;
+}
+#endif  /* HAVE_FILE_HANDLE */
+
+/* read all cgroups in the system and save them in the rbtree */
+void read_all_cgroups(struct rb_root *root);
+
+int cgroup_is_v2(const char *subsys);
+
+#endif /* __CGROUP_H__ */