From 5a26db5bd25cf4bf32ae9fa9f6136b6b6d5b45c5 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 16 Jan 2008 09:51:58 +0100 Subject: lockdep: fix internal double unlock during self-test Lockdep, during self-test (when it was simulating double unlocks) was sometimes unconditionally unlocking a spinlock when it had not been locked. This won't work for ticket locks. Signed-off-by: Nick Piggin Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra --- kernel/lockdep.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 723bd9f92556..4335f12a27c6 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2943,9 +2943,10 @@ void lockdep_free_key_range(void *start, unsigned long size) struct list_head *head; unsigned long flags; int i; + int locked; raw_local_irq_save(flags); - graph_lock(); + locked = graph_lock(); /* * Unhash all classes that were created by this module: @@ -2959,7 +2960,8 @@ void lockdep_free_key_range(void *start, unsigned long size) zap_class(class); } - graph_unlock(); + if (locked) + graph_unlock(); raw_local_irq_restore(flags); } @@ -2969,6 +2971,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) struct list_head *head; unsigned long flags; int i, j; + int locked; raw_local_irq_save(flags); @@ -2987,7 +2990,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) * Debug check: in the end all mapped classes should * be gone. */ - graph_lock(); + locked = graph_lock(); for (i = 0; i < CLASSHASH_SIZE; i++) { head = classhash_table + i; if (list_empty(head)) @@ -3000,7 +3003,8 @@ void lockdep_reset_lock(struct lockdep_map *lock) } } } - graph_unlock(); + if (locked) + graph_unlock(); out_restore: raw_local_irq_restore(flags); -- cgit v1.2.2 From eb13ba873881abd5e15af784756a61af635e665e Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 16 Jan 2008 09:51:58 +0100 Subject: lockdep: fix workqueue creation API lockdep interaction Dave Young reported warnings from lockdep that the workqueue API can sometimes try to register lockdep classes with the same key but different names. This is not permitted in lockdep. Unfortunately, I was unaware of that restriction when I wrote the code to debug workqueue problems with lockdep and used the workqueue name as the lockdep class name. This can obviously lead to the problem if the workqueue name is dynamic. This patch solves the problem by always using a constant name for the workqueue's lockdep class, namely either the constant name that was passed in or a string consisting of the variable name. Signed-off-by: Johannes Berg Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra --- kernel/workqueue.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 52d5e7c9a8e6..8db0b597509e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -722,7 +722,8 @@ static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) struct workqueue_struct *__create_workqueue_key(const char *name, int singlethread, int freezeable, - struct lock_class_key *key) + struct lock_class_key *key, + const char *lock_name) { struct workqueue_struct *wq; struct cpu_workqueue_struct *cwq; @@ -739,7 +740,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name, } wq->name = name; - lockdep_init_map(&wq->lockdep_map, name, key, 0); + lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); wq->singlethread = singlethread; wq->freezeable = freezeable; INIT_LIST_HEAD(&wq->list); -- cgit v1.2.2