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, 126 insertions, 0 deletions

diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
new file mode 100644
index 000000000..87a0818a8
--- /dev/null
+++ b/tools/perf/util/util.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_UTIL_H
+#define __PERF_UTIL_H
+
+#define _BSD_SOURCE 1
+/* glibc 2.20 deprecates _BSD_SOURCE in favour of _DEFAULT_SOURCE */
+#define _DEFAULT_SOURCE 1
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <linux/compiler.h>
+#include <linux/bitmap.h>
+#include <sys/types.h>
+#ifndef __cplusplus
+#include <internal/cpumap.h>
+#endif
+
+extern const char perf_usage_string[];
+extern const char perf_more_info_string[];
+
+extern const char *input_name;
+
+/* This will control if perf_{host,guest} will set attr.exclude_{host,guest}. */
+extern bool exclude_GH_default;
+
+extern bool perf_host;
+extern bool perf_guest;
+
+/* General helper functions */
+void usage(const char *err) __noreturn;
+
+struct dirent;
+struct strlist;
+
+int mkdir_p(char *path, mode_t mode);
+int rm_rf(const char *path);
+int rm_rf_perf_data(const char *path);
+struct strlist *lsdir(const char *name, bool (*filter)(const char *, struct dirent *));
+bool lsdir_no_dot_filter(const char *name, struct dirent *d);
+
+size_t hex_width(u64 v);
+
+int sysctl__max_stack(void);
+
+bool sysctl__nmi_watchdog_enabled(void);
+
+int perf_tip(char **strp, const char *dirpath);
+
+void cpumask_to_cpulist(char *cpumask, char *cpulist);
+
+void print_separator2(int pre_dash_cnt, const char *s, int post_dash_cnt);
+
+#ifndef HAVE_SCHED_GETCPU_SUPPORT
+int sched_getcpu(void);
+#endif
+
+#ifndef HAVE_SCANDIRAT_SUPPORT
+int scandirat(int dirfd, const char *dirp,
+	      struct dirent ***namelist,
+	      int (*filter)(const struct dirent *),
+	      int (*compar)(const struct dirent **, const struct dirent **));
+#endif
+
+extern bool perf_singlethreaded;
+
+void perf_set_singlethreaded(void);
+void perf_set_multithreaded(void);
+
+char *perf_exe(char *buf, int len);
+
+#ifndef O_CLOEXEC
+#ifdef __sparc__
+#define O_CLOEXEC      0x400000
+#elif defined(__alpha__) || defined(__hppa__)
+#define O_CLOEXEC      010000000
+#else
+#define O_CLOEXEC      02000000
+#endif
+#endif
+
+struct perf_debuginfod {
+	const char	*urls;
+	bool		 set;
+};
+void perf_debuginfod_setup(struct perf_debuginfod *di);
+
+const char *perf_basename(const char *path);
+
+char *filename_with_chroot(int pid, const char *filename);
+
+int do_realloc_array_as_needed(void **arr, size_t *arr_sz, size_t x,
+			       size_t msz, const void *init_val);
+
+#define realloc_array_as_needed(a, n, x, v) ({			\
+	typeof(x) __x = (x);					\
+	__x >= (n) ?						\
+		do_realloc_array_as_needed((void **)&(a),	\
+					   &(n),		\
+					   __x,			\
+					   sizeof(*(a)),	\
+					   (const void *)(v)) :	\
+		0;						\
+	})
+
+static inline bool host_is_bigendian(void)
+{
+#ifdef __BYTE_ORDER__
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return false;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	return true;
+#else
+#error "Unrecognized __BYTE_ORDER__"
+#endif
+#else /* !__BYTE_ORDER__ */
+	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0};
+	unsigned int *ptr;
+
+	ptr = (unsigned int *)(void *)str;
+	return *ptr == 0x01020304;
+#endif
+}
+
+#endif /* __PERF_UTIL_H */