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Date: Mon, 12 Jan 2015 09:57:09 -0500
From: Sasha Levin <sasha.levin@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: peterz@...radead.org, mingo@...hat.com,
Sasha Levin <sasha.levin@...cle.com>
Subject: [RFC 2/4] locking/mutex: additional lock information when dumping locks
Show the counter and the owner of the lock when dumping held locks in the
system.
This is useful to figure out who really holds a lock and how many waiters
it has.
Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
drivers/usb/storage/usb.c | 2 +-
fs/inode.c | 3 ++-
fs/super.c | 3 ++-
include/linux/lockdep.h | 2 +-
include/linux/mutex-debug.h | 2 ++
include/linux/mutex.h | 2 +-
kernel/events/core.c | 3 ++-
kernel/locking/lockdep.c | 8 +++++++-
kernel/locking/mutex-debug.c | 14 +++++++++++++-
9 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index d468d02..b0a2565 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -165,7 +165,7 @@ static void us_set_lock_class(struct mutex *mutex,
BUG_ON(i == config->desc.bNumInterfaces);
- lockdep_set_class(mutex, &us_interface_key[i]);
+ lockdep_set_class_type(mutex, &us_interface_key[i], LOCKTYPE_MUTEX);
}
#else
diff --git a/fs/inode.c b/fs/inode.c
index 3a53b1d..8e24ff7 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -160,7 +160,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
mutex_init(&inode->i_mutex);
- lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
+ lockdep_set_class_type(&inode->i_mutex, &sb->s_type->i_mutex_key,
+ LOCKTYPE_MUTEX);
atomic_set(&inode->i_dio_count, 0);
diff --git a/fs/super.c b/fs/super.c
index eae088f..d6b585c 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -217,7 +217,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
s->s_count = 1;
atomic_set(&s->s_active, 1);
mutex_init(&s->s_vfs_rename_mutex);
- lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
+ lockdep_set_class_type(&s->s_vfs_rename_mutex,
+ &type->s_vfs_rename_key, LOCKTYPE_MUTEX);
mutex_init(&s->s_dquot.dqio_mutex);
mutex_init(&s->s_dquot.dqonoff_mutex);
s->s_maxbytes = MAX_NON_LFS;
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 2f4c3fe..cab929b 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -143,7 +143,7 @@ struct lock_class_stats lock_stats(struct lock_class *class);
void clear_lock_stats(struct lock_class *class);
#endif
-enum LOCK_TYPE { LOCKTYPE_NONE, };
+enum LOCK_TYPE { LOCKTYPE_NONE, LOCKTYPE_MUTEX, };
/*
* Map the lock object (the lock instance) to the lock-class object.
diff --git a/include/linux/mutex-debug.h b/include/linux/mutex-debug.h
index 4ac8b19..ed125d3 100644
--- a/include/linux/mutex-debug.h
+++ b/include/linux/mutex-debug.h
@@ -21,4 +21,6 @@ do { \
extern void mutex_destroy(struct mutex *lock);
+extern void mutex_print_debug(const struct mutex *lock);
+
#endif
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index cc31498..cba876d 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -102,7 +102,7 @@ static inline void mutex_destroy(struct mutex *lock) {}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
- , .dep_map = { .name = #lockname }
+ , .dep_map = { .name = #lockname, .type = LOCKTYPE_MUTEX }
#else
# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
#endif
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4c1ee7f..fef4343 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6777,7 +6777,8 @@ skip_type:
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
__perf_event_init_context(&cpuctx->ctx);
- lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
+ lockdep_set_class_type(&cpuctx->ctx.mutex, &cpuctx_mutex,
+ LOCKTYPE_MUTEX);
lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
cpuctx->ctx.type = cpu_context;
cpuctx->ctx.pmu = pmu;
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index de4c9aa..07c337d 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -510,8 +510,14 @@ void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
static void get_lock_info(enum LOCK_TYPE t, struct lockdep_map *map)
{
+ struct mutex *mtx;
+
switch (t) {
- case LOCKTYPE_NONE: return;
+ case LOCKTYPE_NONE: break;
+ case LOCKTYPE_MUTEX:
+ mtx = container_of(map, struct mutex, dep_map);
+ mutex_print_debug(mtx);
+ break;
}
}
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 5cf6731..e97f763 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -98,7 +98,7 @@ void debug_mutex_init(struct mutex *lock, const char *name,
* Make sure we are not reinitializing a held lock:
*/
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
- lockdep_init_map(&lock->dep_map, name, key, 0);
+ lockdep_init_map_type(&lock->dep_map, name, key, 0, LOCKTYPE_MUTEX);
#endif
lock->magic = lock;
}
@@ -118,3 +118,15 @@ void mutex_destroy(struct mutex *lock)
}
EXPORT_SYMBOL_GPL(mutex_destroy);
+
+void mutex_print_debug(const struct mutex *lock)
+{
+ const char *owner = "None";
+ int c = atomic_read(&lock->count);
+
+ if (lock->owner)
+ owner = lock->owner->comm;
+
+ printk("Mutex: counter: %d owner: %s\n", c, owner);
+}
+EXPORT_SYMBOL_GPL(mutex_print_debug);
--
1.7.10.4
--
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