Commit 4d9f34ad authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
Browse files

[PATCH] lockdep: kconfig



Offer the following lock validation options:

 CONFIG_PROVE_LOCKING
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ef5d4707
......@@ -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
......
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