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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

51
kernel/mutex-debug.c
View file

@ -20,52 +20,19 @@
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include "mutex-debug.h"
/*
* We need a global lock when we walk through the multi-process
* lock tree. Only used in the deadlock-debugging case.
*/
DEFINE_SPINLOCK(debug_mutex_lock);
/*
* All locks held by all tasks, in a single global list:
*/
LIST_HEAD(debug_mutex_held_locks);
/*
* In the debug case we carry the caller's instruction pointer into
* other functions, but we dont want the function argument overhead
* in the nondebug case - hence these macros:
*/
#define __IP_DECL__ , unsigned long ip
#define __IP__ , ip
#define __RET_IP__ , (unsigned long)__builtin_return_address(0)
/*
* "mutex debugging enabled" flag. We turn it off when we detect
* the first problem because we dont want to recurse back
* into the tracing code when doing error printk or
* executing a BUG():
*/
int debug_mutex_on = 1;
/*
* Must be called with lock->wait_lock held.
*/
void debug_mutex_set_owner(struct mutex *lock,
struct thread_info *new_owner __IP_DECL__)
void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
{
lock->owner = new_owner;
DEBUG_LOCKS_WARN_ON(!list_empty(&lock->held_list));
if (debug_mutex_on) {
list_add_tail(&lock->held_list, &debug_mutex_held_locks);
lock->acquire_ip = ip;
}
}
void debug_mutex_init_waiter(struct mutex_waiter *waiter)
void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
{
memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
waiter->magic = waiter;
@ -87,9 +54,10 @@ void debug_mutex_free_waiter(struct mutex_waiter *waiter)
}
void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
struct thread_info *ti __IP_DECL__)
struct thread_info *ti)
{
SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
/* Mark the current thread as blocked on the lock: */
ti->task->blocked_on = waiter;
waiter->lock = lock;
@ -109,13 +77,10 @@ void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
void debug_mutex_unlock(struct mutex *lock)
{
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
if (debug_mutex_on) {
DEBUG_LOCKS_WARN_ON(list_empty(&lock->held_list));
list_del_init(&lock->held_list);
}
}
void debug_mutex_init(struct mutex *lock, const char *name)
@ -123,10 +88,8 @@ void debug_mutex_init(struct mutex *lock, const char *name)
/*
* Make sure we are not reinitializing a held lock:
*/
mutex_debug_check_no_locks_freed((void *)lock, sizeof(*lock));
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lock->owner = NULL;
INIT_LIST_HEAD(&lock->held_list);
lock->name = name;
lock->magic = lock;
}