[PATCH] lockdep: better lock debugging
Generic lock debugging:
- generalized lock debugging framework. For example, a bug in one lock
subsystem turns off debugging in all lock subsystems.
- got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
the mutex/rtmutex debugging code: it caused way too much prototype
hackery, and lockdep will give the same information anyway.
- ability to do silent tests
- check lock freeing in vfree too.
- more finegrained debugging options, to allow distributions to
turn off more expensive debugging features.
There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes. (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)
Here are the current debugging options:
CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y
which do:
config DEBUG_MUTEXES
bool "Mutex debugging, basic checks"
config DEBUG_LOCK_ALLOC
bool "Detect incorrect freeing of live mutexes"
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/kernel/sched.c b/kernel/sched.c
index d5e3707..48c1faa 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -30,6 +30,7 @@
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/kernel_stat.h>
+#include <linux/debug_locks.h>
#include <linux/security.h>
#include <linux/notifier.h>
#include <linux/profile.h>
@@ -3142,12 +3143,13 @@
/*
* Underflow?
*/
- BUG_ON((preempt_count() < 0));
+ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+ return;
preempt_count() += val;
/*
* Spinlock count overflowing soon?
*/
- BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
+ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
}
EXPORT_SYMBOL(add_preempt_count);
@@ -3156,11 +3158,15 @@
/*
* Underflow?
*/
- BUG_ON(val > preempt_count());
+ if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+ return;
/*
* Is the spinlock portion underflowing?
*/
- BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
+ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+ !(preempt_count() & PREEMPT_MASK)))
+ return;
+
preempt_count() -= val;
}
EXPORT_SYMBOL(sub_preempt_count);
@@ -4690,7 +4696,7 @@
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
- mutex_debug_show_all_locks();
+ debug_show_all_locks();
}
/**
