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, 119 insertions, 0 deletions

diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
new file mode 100644
index 000000000..bf633cde8
--- /dev/null
+++ b/tools/testing/vsock/util.h
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <sys/socket.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/vm_sockets.h>
+
+/* All known vsock transports, see callers of vsock_core_register() */
+#define KNOWN_TRANSPORTS(x)		\
+	x(LOOPBACK, "loopback")		\
+	x(VIRTIO, "virtio")		\
+	x(VHOST, "vhost")		\
+	x(VMCI, "vmci")			\
+	x(HYPERV, "hvs")
+
+enum transport {
+	TRANSPORT_COUNTER_BASE = __COUNTER__ + 1,
+	#define x(name, symbol)		\
+		TRANSPORT_##name = BIT(__COUNTER__ - TRANSPORT_COUNTER_BASE),
+	KNOWN_TRANSPORTS(x)
+	TRANSPORT_NUM = __COUNTER__ - TRANSPORT_COUNTER_BASE,
+	#undef x
+};
+
+static const char * const transport_ksyms[] = {
+	#define x(name, symbol) " " symbol "_transport",
+	KNOWN_TRANSPORTS(x)
+	#undef x
+};
+
+static_assert(ARRAY_SIZE(transport_ksyms) == TRANSPORT_NUM);
+static_assert(BITS_PER_TYPE(int) >= TRANSPORT_NUM);
+
+#define TRANSPORTS_G2H   (TRANSPORT_VIRTIO | TRANSPORT_VMCI | TRANSPORT_HYPERV)
+#define TRANSPORTS_H2G   (TRANSPORT_VHOST | TRANSPORT_VMCI)
+#define TRANSPORTS_LOCAL (TRANSPORT_LOOPBACK)
+
+/* Tests can either run as the client or the server */
+enum test_mode {
+	TEST_MODE_UNSET,
+	TEST_MODE_CLIENT,
+	TEST_MODE_SERVER
+};
+
+#define DEFAULT_PEER_PORT	1234
+
+/* Test runner options */
+struct test_opts {
+	enum test_mode mode;
+	unsigned int peer_cid;
+	unsigned int peer_port;
+};
+
+/* A test case definition.  Test functions must print failures to stderr and
+ * terminate with exit(EXIT_FAILURE).
+ */
+struct test_case {
+	const char *name; /* human-readable name */
+
+	/* Called when test mode is TEST_MODE_CLIENT */
+	void (*run_client)(const struct test_opts *opts);
+
+	/* Called when test mode is TEST_MODE_SERVER */
+	void (*run_server)(const struct test_opts *opts);
+
+	bool skip;
+};
+
+void init_signals(void);
+unsigned int parse_cid(const char *str);
+unsigned int parse_port(const char *str);
+int vsock_connect_fd(int fd, unsigned int cid, unsigned int port);
+int vsock_connect(unsigned int cid, unsigned int port, int type);
+int vsock_accept(unsigned int cid, unsigned int port,
+		 struct sockaddr_vm *clientaddrp, int type);
+int vsock_stream_connect(unsigned int cid, unsigned int port);
+int vsock_bind_try(unsigned int cid, unsigned int port, int type);
+int vsock_bind(unsigned int cid, unsigned int port, int type);
+int vsock_bind_connect(unsigned int cid, unsigned int port,
+		       unsigned int bind_port, int type);
+int vsock_seqpacket_connect(unsigned int cid, unsigned int port);
+int vsock_stream_accept(unsigned int cid, unsigned int port,
+			struct sockaddr_vm *clientaddrp);
+int vsock_stream_listen(unsigned int cid, unsigned int port);
+int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
+			   struct sockaddr_vm *clientaddrp);
+void vsock_wait_remote_close(int fd);
+bool vsock_ioctl_int(int fd, unsigned long op, int expected);
+bool vsock_wait_sent(int fd);
+void send_buf(int fd, const void *buf, size_t len, int flags,
+	      ssize_t expected_ret);
+void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret);
+void send_byte(int fd, int expected_ret, int flags);
+void recv_byte(int fd, int expected_ret, int flags);
+void run_tests(const struct test_case *test_cases,
+	       const struct test_opts *opts);
+void list_tests(const struct test_case *test_cases);
+void skip_test(struct test_case *test_cases, size_t test_cases_len,
+	       const char *test_id_str);
+void pick_test(struct test_case *test_cases, size_t test_cases_len,
+	       const char *test_id_str);
+unsigned long hash_djb2(const void *data, size_t len);
+size_t iovec_bytes(const struct iovec *iov, size_t iovnum);
+unsigned long iovec_hash_djb2(const struct iovec *iov, size_t iovnum);
+struct iovec *alloc_test_iovec(const struct iovec *test_iovec, int iovnum);
+void free_test_iovec(const struct iovec *test_iovec,
+		     struct iovec *iovec, int iovnum);
+void setsockopt_ull_check(int fd, int level, int optname,
+			  unsigned long long val, char const *errmsg);
+void setsockopt_int_check(int fd, int level, int optname, int val,
+			  char const *errmsg);
+void setsockopt_timeval_check(int fd, int level, int optname,
+			      struct timeval val, char const *errmsg);
+void enable_so_zerocopy_check(int fd);
+void enable_so_linger(int fd, int timeout);
+int get_transports(void);
+#endif /* UTIL_H */