From e4bc16044e1b80636855dbc39da1d121a3508308 Mon Sep 17 00:00:00 2001
From: Casey Bodley <cbodley@redhat.com>
Date: Thu, 14 Jul 2016 13:38:44 -0400
Subject: [PATCH] rgw: RGWMetaSyncCR holds refs to stacks for wakeup

because RGWCoroutine::wakeup() calls RGWCoroutinesStack::wakeup(), the
stack must also stay alive

Fixes: http://tracker.ceph.com/issues/16666

Signed-off-by: Casey Bodley <cbodley@redhat.com>
---
 src/rgw/rgw_sync.cc | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/rgw/rgw_sync.cc b/src/rgw/rgw_sync.cc
index c53a2cd5da649..474e2c558d87f 100644
--- a/src/rgw/rgw_sync.cc
+++ b/src/rgw/rgw_sync.cc
@@ -1668,8 +1668,13 @@ class RGWMetaSyncCR : public RGWCoroutine {
 
   std::mutex mutex; //< protect access to shard_crs
 
+  // TODO: it should be enough to hold a reference on the stack only, as calling
+  // RGWCoroutinesStack::wakeup() doesn't refer to the RGWCoroutine if it has
+  // already completed
   using ControlCRRef = boost::intrusive_ptr<RGWMetaSyncShardControlCR>;
-  map<int, ControlCRRef> shard_crs;
+  using StackRef = boost::intrusive_ptr<RGWCoroutinesStack>;
+  using RefPair = std::pair<ControlCRRef, StackRef>;
+  map<int, RefPair> shard_crs;
 
 public:
   RGWMetaSyncCR(RGWMetaSyncEnv *_sync_env, RGWPeriodHistory::Cursor cursor,
@@ -1727,8 +1732,8 @@ class RGWMetaSyncCR : public RGWCoroutine {
             auto cr = new RGWMetaSyncShardControlCR(sync_env, pool, period_id,
                                                     mdlog, shard_id, marker,
                                                     std::move(period_marker));
-            shard_crs[shard_id] = cr;
-            spawn(cr, false);
+            auto stack = spawn(cr, false);
+            shard_crs[shard_id] = RefPair{cr, stack};
           }
         }
         // wait for each shard to complete
@@ -1764,7 +1769,7 @@ class RGWMetaSyncCR : public RGWCoroutine {
     if (iter == shard_crs.end()) {
       return;
     }
-    iter->second->wakeup();
+    iter->second.first->wakeup();
   }
 };