Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 9e55f87c0e3b · 2019-03-10T13:48:14.000-07:00
Pull locking fixes from Thomas Gleixner:
 "A few fixes for lockdep:

   - initialize lockdep internal RCU head after initializing RCU

   - prevent use after free in a alloc_workqueue() error handling path

   - plug a memory leak in the workqueue core which fails to free a
     dynamically allocated lock name.

   - make Clang happy"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  workqueue, lockdep: Fix a memory leak in wq-&gt;lock_name
  workqueue, lockdep: Fix an alloc_workqueue() error path
  locking/lockdep: Only call init_rcu_head() after RCU has been initialized
  locking/lockdep: Avoid a Clang warning
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
@@ -842,7 +842,9 @@ static bool class_lock_list_valid(struct lock_class *c, struct list_head *h)
 	return true;
 }
 
-static u16 chain_hlocks[];
+#ifdef CONFIG_PROVE_LOCKING
+static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
+#endif
 
 static bool check_lock_chain_key(struct lock_chain *chain)
 {
@@ -980,15 +982,22 @@ static inline void check_data_structures(void) { }
  */
 static void init_data_structures_once(void)
 {
-	static bool initialization_happened;
+	static bool ds_initialized, rcu_head_initialized;
 	int i;
 
-	if (likely(initialization_happened))
+	if (likely(rcu_head_initialized))
+		return;
+
+	if (system_state >= SYSTEM_SCHEDULING) {
+		init_rcu_head(&delayed_free.rcu_head);
+		rcu_head_initialized = true;
+	}
+
+	if (ds_initialized)
 		return;
 
-	initialization_happened = true;
+	ds_initialized = true;
 
-	init_rcu_head(&delayed_free.rcu_head);
 	INIT_LIST_HEAD(&delayed_free.pf[0].zapped);
 	INIT_LIST_HEAD(&delayed_free.pf[1].zapped);
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
@@ -3445,6 +3445,8 @@ static void wq_init_lockdep(struct workqueue_struct *wq)
 	lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
 	if (!lock_name)
 		lock_name = wq->name;
+
+	wq->lock_name = lock_name;
 	lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
 }
 
@@ -4291,6 +4293,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 	return wq;
 
 err_free_wq:
+	wq_unregister_lockdep(wq);
+	wq_free_lockdep(wq);
 	free_workqueue_attrs(wq->unbound_attrs);
 	kfree(wq);
 	return NULL;
