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[PATCH] lockdep: better lock debugging

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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>
This commit is contained in:
Ingo Molnar 2006-07-03 00:24:33 -07:00 • committed by Linus Torvalds
parent fb7e42413a
commit 9a11b49a80
25 changed files with 264 additions and 566 deletions
Download patch file Download diff file Expand all files Collapse all files

16
kernel/sched.c
View file

@ -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 @@ void fastcall add_preempt_count(int val)
/*
* 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 @@ void fastcall sub_preempt_count(int val)
/*
* 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 @@ void show_state(void)
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
mutex_debug_show_all_locks();
debug_show_all_locks();
}
/**