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, 39 insertions, 0 deletions

diff --git a/scripts/Makefile.propeller b/scripts/Makefile.propeller
new file mode 100644
index 000000000..48a660128
--- /dev/null
+++ b/scripts/Makefile.propeller
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Enable available and selected Clang Propeller features.
+ifdef CLANG_PROPELLER_PROFILE_PREFIX
+  CFLAGS_PROPELLER_CLANG := -fbasic-block-sections=list=$(CLANG_PROPELLER_PROFILE_PREFIX)_cc_profile.txt -ffunction-sections
+  KBUILD_LDFLAGS += --symbol-ordering-file=$(CLANG_PROPELLER_PROFILE_PREFIX)_ld_profile.txt --no-warn-symbol-ordering
+else
+  # Starting with Clang v20, the '-fbasic-block-sections=labels' option is
+  # deprecated. Use the recommended '-fbasic-block-address-map' option.
+  # Link: https://github.com/llvm/llvm-project/pull/110039
+  ifeq ($(call clang-min-version, 200000),y)
+    CFLAGS_PROPELLER_CLANG := -fbasic-block-address-map
+  else
+    CFLAGS_PROPELLER_CLANG := -fbasic-block-sections=labels
+  endif
+endif
+
+# Propeller requires debug information to embed module names in the profiles.
+# If CONFIG_DEBUG_INFO is not enabled, set -gmlt option. Skip this for AutoFDO,
+# as the option should already be set.
+ifndef CONFIG_DEBUG_INFO
+  ifndef CONFIG_AUTOFDO_CLANG
+    CFLAGS_PROPELLER_CLANG += -gmlt
+  endif
+endif
+
+ifdef CONFIG_LTO_CLANG_THIN
+  ifdef CLANG_PROPELLER_PROFILE_PREFIX
+    KBUILD_LDFLAGS += --lto-basic-block-sections=$(CLANG_PROPELLER_PROFILE_PREFIX)_cc_profile.txt
+  else
+    ifeq ($(call test-ge, $(CONFIG_LLD_VERSION), 200000),y)
+       KBUILD_LDFLAGS += --lto-basic-block-address-map
+    else
+       KBUILD_LDFLAGS += --lto-basic-block-sections=labels
+    endif
+  endif
+endif
+
+export CFLAGS_PROPELLER_CLANG