locktorture: Add a lock-torture kernel module

This commit adds the locking counterpart to rcutorture.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Make n_lock_torture_errors and torture_spinlock static
  as suggested by Fengguang Wu. ]
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

kernel/locking/Makefile

@@ -23,3 +23,4 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
 obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
+obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o

lib/Kconfig.debug

@@ -980,6 +980,21 @@ config DEBUG_LOCKING_API_SELFTESTS
 	  The following locking APIs are covered: spinlocks, rwlocks,
 	  mutexes and rwsems.
 
+config LOCK_TORTURE_TEST
+	tristate "torture tests for locking"
+	depends on DEBUG_KERNEL
+	select TORTURE_TEST
+	default n
+	help
+	  This option provides a kernel module that runs torture tests
+	  on kernel locking primitives.  The kernel module may be built
+	  after the fact on the running kernel to be tested, if desired.
+
+	  Say Y here if you want kernel locking-primitive torture tests
+	  to be built into the kernel.
+	  Say M if you want these torture tests to build as a module.
+	  Say N if you are unsure.
+
 endmenu # lock debugging
 
 config TRACE_IRQFLAGS