locking/lockdep: Only call init_rcu_head() after RCU has been initialized

init_data_structures_once() is called for the first time before RCU has
been initialized. Make sure that init_rcu_head() is called before the
RCU head is used and after RCU has been initialized.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: longman@redhat.com
Link: https://lkml.kernel.org/r/c20aa0f0-42ab-a884-d931-7d4ec2bf0cdc@acm.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel/locking/lockdep.c

@@ -982,15 +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;
 
-	initialization_happened = true;
+	if (system_state >= SYSTEM_SCHEDULING) {
+		init_rcu_head(&delayed_free.rcu_head);
+		rcu_head_initialized = true;
+	}
+
+	if (ds_initialized)
+		return;
+
+	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);