[PATCH] lockdep: locking API self tests

Introduce DEBUG_LOCKING_API_SELFTESTS, which uses the generic lock debugging
code's silent-failure feature to run a matrix of testcases.  There are 210
testcases currently:

  +-----------------------
  | Locking API testsuite:
  +------------------------------+------+------+------+------+------+------+
                                 | spin |wlock |rlock |mutex | wsem | rsem |
  -------------------------------+------+------+------+------+------+------+
                     A-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                 A-B-B-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
             A-B-B-C-C-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
             A-B-C-A-B-C deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
         A-B-B-C-C-D-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
         A-B-C-D-B-D-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
         A-B-C-D-B-C-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                    double unlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                 bad unlock order:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
  --------------------------------------+------+------+------+------+------+
              recursive read-lock:             |  ok  |             |  ok  |
  --------------------------------------+------+------+------+------+------+
                non-nested unlock:  ok  |  ok  |  ok  |  ok  |
  --------------------------------------+------+------+------+
     hard-irqs-on + irq-safe-A/12:  ok  |  ok  |  ok  |
     soft-irqs-on + irq-safe-A/12:  ok  |  ok  |  ok  |
     hard-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
     soft-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
       sirq-safe-A => hirqs-on/12:  ok  |  ok  |  ok  |
       sirq-safe-A => hirqs-on/21:  ok  |  ok  |  ok  |
         hard-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
         soft-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
         hard-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
         soft-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/132:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/132:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/213:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/213:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/231:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/231:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/312:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/312:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #1/321:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #1/321:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/123:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/123:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/132:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/132:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/213:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/213:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/231:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/231:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/312:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/312:  ok  |  ok  |  ok  |
    hard-safe-A + unsafe-B #2/321:  ok  |  ok  |  ok  |
    soft-safe-A + unsafe-B #2/321:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/123:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/123:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/132:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/132:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/213:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/213:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/231:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/231:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/312:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/312:  ok  |  ok  |  ok  |
      hard-irq lock-inversion/321:  ok  |  ok  |  ok  |
      soft-irq lock-inversion/321:  ok  |  ok  |  ok  |
      hard-irq read-recursion/123:  ok  |
      soft-irq read-recursion/123:  ok  |
      hard-irq read-recursion/132:  ok  |
      soft-irq read-recursion/132:  ok  |
      hard-irq read-recursion/213:  ok  |
      soft-irq read-recursion/213:  ok  |
      hard-irq read-recursion/231:  ok  |
      soft-irq read-recursion/231:  ok  |
      hard-irq read-recursion/312:  ok  |
      soft-irq read-recursion/312:  ok  |
      hard-irq read-recursion/321:  ok  |
      soft-irq read-recursion/321:  ok  |
  --------------------------------+-----+----------------
  Good, all 210 testcases passed! |
  --------------------------------+
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Documentation/kernel-parameters.txt

@@ -435,6 +435,15 @@ running once the system is up.
 
 	debug		[KNL] Enable kernel debugging (events log level).
 
+	debug_locks_verbose=
+			[KNL] verbose self-tests
+			Format=<0|1>
+			Print debugging info while doing the locking API
+			self-tests.
+			We default to 0 (no extra messages), setting it to
+			1 will print _a lot_ more information - normally
+			only useful to kernel developers.
+
 	decnet=		[HW,NET]
 			Format: <area>[,<node>]
 			See also Documentation/networking/decnet.txt.

lib/Kconfig.debug

@@ -149,6 +149,17 @@ config DEBUG_SPINLOCK_SLEEP
 	  If you say Y here, various routines which may sleep will become very
 	  noisy if they are called with a spinlock held.
 
+config DEBUG_LOCKING_API_SELFTESTS
+	bool "Locking API boot-time self-tests"
+	depends on DEBUG_KERNEL
+	help
+	  Say Y here if you want the kernel to run a short self-test during
+	  bootup. The self-test checks whether common types of locking bugs
+	  are detected by debugging mechanisms or not. (if you disable
+	  lock debugging then those bugs wont be detected of course.)
+	  The following locking APIs are covered: spinlocks, rwlocks,
+	  mutexes and rwsems.
+
 config STACKTRACE
 	bool
 	depends on STACKTRACE_SUPPORT

lib/Makefile

@@ -18,6 +18,7 @@ CFLAGS_kobject.o += -DDEBUG
 CFLAGS_kobject_uevent.o += -DDEBUG
 endif
 
+obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o

lib/locking-selftest-hardirq.h

+#undef IRQ_DISABLE
+#undef IRQ_ENABLE
+#undef IRQ_ENTER
+#undef IRQ_EXIT
+
+#define IRQ_ENABLE		HARDIRQ_ENABLE
+#define IRQ_DISABLE		HARDIRQ_DISABLE
+#define IRQ_ENTER		HARDIRQ_ENTER
+#define IRQ_EXIT		HARDIRQ_EXIT

lib/locking-selftest-mutex.h

+#undef LOCK
+#define LOCK		ML
+
+#undef UNLOCK
+#define UNLOCK		MU
+
+#undef RLOCK
+#undef WLOCK
+
+#undef INIT
+#define INIT		MI

lib/locking-selftest-rlock-hardirq.h

+#include "locking-selftest-rlock.h"
+#include "locking-selftest-hardirq.h"

lib/locking-selftest-rlock-softirq.h

+#include "locking-selftest-rlock.h"
+#include "locking-selftest-softirq.h"

lib/locking-selftest-rlock.h

+#undef LOCK
+#define LOCK		RL
+
+#undef UNLOCK
+#define UNLOCK		RU
+
+#undef RLOCK
+#define RLOCK		RL
+
+#undef WLOCK
+#define WLOCK		WL
+
+#undef INIT
+#define INIT		RWI

lib/locking-selftest-rsem.h

+#undef LOCK
+#define LOCK		RSL
+
+#undef UNLOCK
+#define UNLOCK		RSU
+
+#undef RLOCK
+#define RLOCK		RSL
+
+#undef WLOCK
+#define WLOCK		WSL
+
+#undef INIT
+#define INIT		RWSI

lib/locking-selftest-softirq.h

+#undef IRQ_DISABLE
+#undef IRQ_ENABLE
+#undef IRQ_ENTER
+#undef IRQ_EXIT
+
+#define IRQ_DISABLE		SOFTIRQ_DISABLE
+#define IRQ_ENABLE		SOFTIRQ_ENABLE
+#define IRQ_ENTER		SOFTIRQ_ENTER
+#define IRQ_EXIT		SOFTIRQ_EXIT

lib/locking-selftest-spin-hardirq.h

+#include "locking-selftest-spin.h"
+#include "locking-selftest-hardirq.h"

lib/locking-selftest-spin-softirq.h

+#include "locking-selftest-spin.h"
+#include "locking-selftest-softirq.h"

lib/locking-selftest-spin.h

+#undef LOCK
+#define LOCK		L
+
+#undef UNLOCK
+#define UNLOCK		U
+
+#undef RLOCK
+#undef WLOCK
+
+#undef INIT
+#define INIT		SI

lib/locking-selftest-wlock-hardirq.h

+#include "locking-selftest-wlock.h"
+#include "locking-selftest-hardirq.h"

lib/locking-selftest-wlock-softirq.h

+#include "locking-selftest-wlock.h"
+#include "locking-selftest-softirq.h"

lib/locking-selftest-wlock.h

+#undef LOCK
+#define LOCK		WL
+
+#undef UNLOCK
+#define UNLOCK		WU
+
+#undef RLOCK
+#define RLOCK		RL
+
+#undef WLOCK
+#define WLOCK		WL
+
+#undef INIT
+#define INIT		RWI

lib/locking-selftest-wsem.h

+#undef LOCK
+#define LOCK		WSL
+
+#undef UNLOCK
+#define UNLOCK		WSU
+
+#undef RLOCK
+#define RLOCK		RSL
+
+#undef WLOCK
+#define WLOCK		WSL
+
+#undef INIT
+#define INIT		RWSI