[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>

1 files changed, 96 insertions, 2 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 16c2e98b7638..e5889b1a33ff 100644
--- 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