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, 64 insertions, 0 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
new file mode 100644
index 000000000..2dba7f83e
--- /dev/null
+++ b/arch/x86/lib/Makefile
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for x86 specific library files.
+#
+
+# Produces uninteresting flaky coverage.
+KCOV_INSTRUMENT_delay.o	:= n
+
+# KCSAN uses udelay for introducing watchpoint delay; avoid recursion.
+KCSAN_SANITIZE_delay.o := n
+ifdef CONFIG_KCSAN
+# In case KCSAN+lockdep+ftrace are enabled, disable ftrace for delay.o to avoid
+# lockdep -> [other libs] -> KCSAN -> udelay -> ftrace -> lockdep recursion.
+CFLAGS_REMOVE_delay.o = $(CC_FLAGS_FTRACE)
+endif
+
+inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk
+inat_tables_maps = $(srctree)/arch/x86/lib/x86-opcode-map.txt
+quiet_cmd_inat_tables = GEN     $@
+      cmd_inat_tables = $(AWK) -f $(inat_tables_script) $(inat_tables_maps) > $@
+
+$(obj)/inat-tables.c: $(inat_tables_script) $(inat_tables_maps)
+	$(call cmd,inat_tables)
+
+$(obj)/inat.o: $(obj)/inat-tables.c
+
+clean-files := inat-tables.c
+
+obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
+
+lib-y := delay.o misc.o cmdline.o cpu.o
+lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
+lib-y += memcpy_$(BITS).o
+lib-y += pc-conf-reg.o
+lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o
+lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
+lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
+lib-$(CONFIG_FUNCTION_ERROR_INJECTION)	+= error-inject.o
+lib-$(CONFIG_MITIGATION_RETPOLINE) += retpoline.o
+
+obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
+obj-y += iomem.o
+
+ifeq ($(CONFIG_X86_32),y)
+        obj-y += atomic64_32.o
+        lib-y += atomic64_cx8_32.o
+        lib-y += checksum_32.o
+        lib-y += strstr_32.o
+        lib-y += string_32.o
+        lib-y += memmove_32.o
+        lib-y += cmpxchg8b_emu.o
+ifneq ($(CONFIG_X86_CX8),y)
+        lib-y += atomic64_386_32.o
+endif
+else
+ifneq ($(CONFIG_GENERIC_CSUM),y)
+        lib-y += csum-partial_64.o csum-copy_64.o csum-wrappers_64.o
+endif
+        lib-y += clear_page_64.o copy_page_64.o
+        lib-y += memmove_64.o memset_64.o
+        lib-y += copy_user_64.o copy_user_uncached_64.o
+        lib-y += cmpxchg16b_emu.o
+        lib-y += bhi.o
+endif