Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "The RCU changes in this cycle are:

   - Dynticks updates, consolidating open-coded counter accesses into a
     well-defined API

   - SRCU updates: Simplify algorithm, add formal verification

   - Documentation updates

   - Miscellaneous fixes

   - Torture-test updates

  Most of the diffstat comes from the relatively large documentation
  update"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  srcu: Reduce probability of SRCU ->unlock_count[] counter overflow
  rcutorture: Add CBMC-based formal verification for SRCU
  srcu: Force full grace-period ordering
  srcu: Implement more-efficient reader counts
  rcu: Adjust FQS offline checks for exact online-CPU detection
  rcu: Check cond_resched_rcu_qs() state less often to reduce GP overhead
  rcu: Abstract extended quiescent state determination
  rcu: Abstract dynticks extended quiescent state enter/exit operations
  rcu: Add lockdep checks to synchronous expedited primitives
  rcu: Eliminate unused expedited_normal counter
  llist: Clarify comments about when locking is needed
  rcu: Fix comment in rcu_organize_nocb_kthreads()
  rcu: Enable RCU tracepoints by default to aid in debugging
  rcu: Make rcu_cpu_starting() use its "cpu" argument
  rcu: Add comment headers to expedited-grace-period counter functions
  rcu: Don't wake rcuc/X kthreads on NOCB CPUs
  rcu: Re-enable TASKS_RCU for User Mode Linux
  rcu: Once again use NMI-based stack traces in stall warnings
  rcu: Remove short-term CPU kicking
  rcu: Add long-term CPU kicking
  ...

8 files changed, 88 insertions, 0 deletions

diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore
new file mode 100644
index 000000000000..f47cb2045f13
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore
@@ -0,0 +1 @@
+*.out
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile
new file mode 100644
index 000000000000..3a3aee149225
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile
@@ -0,0 +1,11 @@
+CBMC_FLAGS = -I../.. -I../../src -I../../include -I../../empty_includes -32 -pointer-check -mm pso
+
+all:
+	for i in ./*.pass; do \
+		echo $$i ; \
+		CBMC_FLAGS="$(CBMC_FLAGS)" sh ../test_script.sh --should-pass $$i > $$i.out 2>&1 ; \
+	done
+	for i in ./*.fail; do \
+		echo $$i ; \
+		CBMC_FLAGS="$(CBMC_FLAGS)" sh ../test_script.sh --should-fail $$i > $$i.out 2>&1 ; \
+	done
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail
new file mode 100644
index 000000000000..40c8075919d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DASSERT_END"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail
new file mode 100644
index 000000000000..ada5baf0b60d
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail
new file mode 100644
index 000000000000..8fe00c8db466
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE_2"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail
new file mode 100644
index 000000000000..612ed6772844
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE_3"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c
new file mode 100644
index 000000000000..470b1105a112
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c
@@ -0,0 +1,72 @@
+#include <src/combined_source.c>
+
+int x;
+int y;
+
+int __unbuffered_tpr_x;
+int __unbuffered_tpr_y;
+
+DEFINE_SRCU(ss);
+
+void rcu_reader(void)
+{
+	int idx;
+
+#ifndef FORCE_FAILURE_3
+	idx = srcu_read_lock(&ss);
+#endif
+	might_sleep();
+
+	__unbuffered_tpr_y = READ_ONCE(y);
+#ifdef FORCE_FAILURE
+	srcu_read_unlock(&ss, idx);
+	idx = srcu_read_lock(&ss);
+#endif
+	WRITE_ONCE(x, 1);
+
+#ifndef FORCE_FAILURE_3
+	srcu_read_unlock(&ss, idx);
+#endif
+	might_sleep();
+}
+
+void *thread_update(void *arg)
+{
+	WRITE_ONCE(y, 1);
+#ifndef FORCE_FAILURE_2
+	synchronize_srcu(&ss);
+#endif
+	might_sleep();
+	__unbuffered_tpr_x = READ_ONCE(x);
+
+	return NULL;
+}
+
+void *thread_process_reader(void *arg)
+{
+	rcu_reader();
+
+	return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	pthread_t tu;
+	pthread_t tpr;
+
+	if (pthread_create(&tu, NULL, thread_update, NULL))
+		abort();
+	if (pthread_create(&tpr, NULL, thread_process_reader, NULL))
+		abort();
+	if (pthread_join(tu, NULL))
+		abort();
+	if (pthread_join(tpr, NULL))
+		abort();
+	assert(__unbuffered_tpr_y != 0 || __unbuffered_tpr_x != 0);
+
+#ifdef ASSERT_END
+	assert(0);
+#endif
+
+	return 0;
+}