From eb3df0b8e48dd22ae7c4bee11be3c455ff66dafb Mon Sep 17 00:00:00 2001
From: Jie Yao <jyao3@ebay.com>
Date: Sun, 17 Sep 2023 04:43:32 -0700
Subject: [PATCH] update

---
 src/lib/homestore/heap_chunk_selector.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/lib/homestore/heap_chunk_selector.cpp b/src/lib/homestore/heap_chunk_selector.cpp
index ed28cfa6..6e2db4e1 100644
--- a/src/lib/homestore/heap_chunk_selector.cpp
+++ b/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();