update

src/lib/homestore/heap_chunk_selector.cpp

@@ -29,10 +29,14 @@ csharedChunk HeapChunkSelector::select_chunk(homestore::blk_count_t count, const
     if(pdevID == homestore::INVALID_DEV_ID) {
     // this is the first shard of this pg, select a pdev with the most available blocks for it
         std::lock_guard<std::mutex> l(lock);
-        auto it = std::max_element(m_pdev_avalable_blk_map.begin(), m_pdev_avalable_blk_map.end(),
+        auto& it = std::max_element(m_pdev_avalable_blk_map.begin(), m_pdev_avalable_blk_map.end(),
         [](const std::pair<uint32_t, uint32_t>& lhs, const std::pair<uint32_t, uint32_t>& rhs) { 
             return lhs.second < rhs.second; }
         );
+        if(it == m_pdev_avalable_blk_map.end()) {
+            LOGINFO("No pdev found for pg");
+            return nullptr;
+        }
         pdevID = it->first;
     }
 
@@ -41,13 +45,13 @@ csharedChunk HeapChunkSelector::select_chunk(homestore::blk_count_t count, const
         LOGINFO("No pdev found for pdev {}", pdevID);
         return nullptr;
     }
-
 
     it->second->first.lock();
     if(it->second->second.empty()) {
         LOGINFO("No more available chunks found for pdev {}", pdevID);
         return nullptr;
     }
+
     auto& vchunk = it->second->second.top();
     it->second->second.pop();
     it->second->first.unlock();