[PATCH] lockdep: kconfig

Offer the following lock validation options:

 CONFIG_PROVE_LOCKING

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 16c2e98b76385ad23cc0e6b5e518aacbe87ee2e3..e5889b1a33ff6fbec48441ee0c158b3323703715 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -134,7 +134,7 @@ config RT_MUTEX_TESTER
          This option enables a rt-mutex tester.
 
 config DEBUG_SPINLOCK
-       bool "Spinlock debugging"
+       bool "Spinlock and rw-lock debugging: basic checks"
        depends on DEBUG_KERNEL
        help
          Say Y here and build SMP to catch missing spinlock initialization
@@ -142,8 +142,102 @@ config DEBUG_SPINLOCK
          best used in conjunction with the NMI watchdog so that spinlock
          deadlocks are also debuggable.
 
+config DEBUG_MUTEXES
+       bool "Mutex debugging: basic checks"
+       depends on DEBUG_KERNEL
+       help
+        This feature allows mutex semantics violations to be detected and
+        reported.
+
+config DEBUG_RWSEMS
+       bool "RW-sem debugging: basic checks"
+       depends on DEBUG_KERNEL
+       help
+        This feature allows read-write semaphore semantics violations to
+        be detected and reported.
+
+config DEBUG_LOCK_ALLOC
+       bool "Lock debugging: detect incorrect freeing of live locks"
+       depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+       select DEBUG_SPINLOCK
+       select DEBUG_MUTEXES
+       select DEBUG_RWSEMS
+       select LOCKDEP
+       help
+        This feature will check whether any held lock (spinlock, rwlock,
+        mutex or rwsem) is incorrectly freed by the kernel, via any of the
+        memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
+        vfree(), etc.), whether a live lock is incorrectly reinitialized via
+        spin_lock_init()/mutex_init()/etc., or whether there is any lock
+        held during task exit.
+
+config PROVE_LOCKING
+       bool "Lock debugging: prove locking correctness"
+       depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+       select LOCKDEP
+       select DEBUG_SPINLOCK
+       select DEBUG_MUTEXES
+       select DEBUG_RWSEMS
+       select DEBUG_LOCK_ALLOC
+       default n
+       help
+        This feature enables the kernel to prove that all locking
+        that occurs in the kernel runtime is mathematically
+        correct: that under no circumstance could an arbitrary (and
+        not yet triggered) combination of observed locking
+        sequences (on an arbitrary number of CPUs, running an
+        arbitrary number of tasks and interrupt contexts) cause a
+        deadlock.
+
+        In short, this feature enables the kernel to report locking
+        related deadlocks before they actually occur.
+
+        The proof does not depend on how hard and complex a
+        deadlock scenario would be to trigger: how many
+        participant CPUs, tasks and irq-contexts would be needed
+        for it to trigger. The proof also does not depend on
+        timing: if a race and a resulting deadlock is possible
+        theoretically (no matter how unlikely the race scenario
+        is), it will be proven so and will immediately be
+        reported by the kernel (once the event is observed that
+        makes the deadlock theoretically possible).
+
+        If a deadlock is impossible (i.e. the locking rules, as
+        observed by the kernel, are mathematically correct), the
+        kernel reports nothing.
+
+        NOTE: this feature can also be enabled for rwlocks, mutexes
+        and rwsems - in which case all dependencies between these
+        different locking variants are observed and mapped too, and
+        the proof of observed correctness is also maintained for an
+        arbitrary combination of these separate locking variants.
+
+        For more details, see Documentation/lockdep-design.txt.
+
+config LOCKDEP
+       bool
+       depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+       select STACKTRACE
+       select FRAME_POINTER
+       select KALLSYMS
+       select KALLSYMS_ALL
+
+config DEBUG_LOCKDEP
+       bool "Lock dependency engine debugging"
+       depends on LOCKDEP
+       help
+         If you say Y here, the lock dependency engine will do
+         additional runtime checks to debug itself, at the price
+         of more runtime overhead.
+
+config TRACE_IRQFLAGS
+       bool
+       default y
+       depends on TRACE_IRQFLAGS_SUPPORT
+       depends on PROVE_LOCKING
+
 config DEBUG_SPINLOCK_SLEEP
-       bool "Sleep-inside-spinlock checking"
+       bool "Spinlock debugging: sleep-inside-spinlock checking"
        depends on DEBUG_KERNEL
        help
          If you say Y here, various routines which may sleep will become very