runtime: fix possible deadlock in bank

runtime/src/bank.rs

@@ -63,6 +63,7 @@ use std::{
     mem,
     ops::RangeInclusive,
     path::PathBuf,
+    ptr,
     rc::Rc,
     sync::atomic::{AtomicBool, AtomicU64, Ordering},
     sync::{Arc, RwLock, RwLockReadGuard},
@@ -2494,6 +2495,9 @@ impl Bank {
     }
 
     pub fn compare_bank(&self, dbank: &Bank) {
+        if ptr::eq(self, dbank) {
+            return;
+        }
         assert_eq!(self.slot, dbank.slot);
         assert_eq!(self.collector_id, dbank.collector_id);
         assert_eq!(self.epoch_schedule, dbank.epoch_schedule);
@@ -2509,14 +2513,14 @@ impl Bank {
             dbank.is_delta.load(Ordering::Relaxed)
         );
 
-        let st = self.stakes.read().unwrap();
-        let dst = dbank.stakes.read().unwrap();
-        assert_eq!(*st, *dst);
-
         let bh = self.hash.read().unwrap();
         let dbh = dbank.hash.read().unwrap();
         assert_eq!(*bh, *dbh);
 
+        let st = self.stakes.read().unwrap();
+        let dst = dbank.stakes.read().unwrap();
+        assert_eq!(*st, *dst);
+
         let bhq = self.blockhash_queue.read().unwrap();
         let dbhq = dbank.blockhash_queue.read().unwrap();
         assert_eq!(*bhq, *dbhq);