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, 42 insertions, 0 deletions

diff --git a/init/noinitramfs.c b/init/noinitramfs.c
new file mode 100644
index 000000000..d1d26b93d
--- /dev/null
+++ b/init/noinitramfs.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * init/noinitramfs.c
+ *
+ * Copyright (C) 2006, NXP Semiconductors, All Rights Reserved
+ * Author: Jean-Paul Saman <jean-paul.saman@nxp.com>
+ */
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/kdev_t.h>
+#include <linux/syscalls.h>
+#include <linux/init_syscalls.h>
+#include <linux/umh.h>
+
+/*
+ * Create a simple rootfs that is similar to the default initramfs
+ */
+static int __init default_rootfs(void)
+{
+	int err;
+
+	usermodehelper_enable();
+	err = init_mkdir("/dev", 0755);
+	if (err < 0)
+		goto out;
+
+	err = init_mknod("/dev/console", S_IFCHR | S_IRUSR | S_IWUSR,
+			new_encode_dev(MKDEV(5, 1)));
+	if (err < 0)
+		goto out;
+
+	err = init_mkdir("/root", 0700);
+	if (err < 0)
+		goto out;
+
+	return 0;
+
+out:
+	printk(KERN_WARNING "Failed to create a rootfs\n");
+	return err;
+}
+rootfs_initcall(default_rootfs);