diff --git a/src/processing/plugins/mock_processor.cc b/src/processing/plugins/mock_processor.cc
index 427e03837fc0..129ce56a3d64 100644
--- a/src/processing/plugins/mock_processor.cc
+++ b/src/processing/plugins/mock_processor.cc
@@ -33,7 +33,7 @@ void* MockProcessor::ProcessGHPairs(std::size_t *size, const std::vector<double>
   }
 
   // Save pairs for future operations
-  this->gh_pairs_ = new std::vector<double>(pairs);
+  this->gh_pairs_ = pairs;
 
   return buf;
 }
@@ -51,9 +51,9 @@ void* MockProcessor::HandleGHPairs(std::size_t *size, void *buffer, std::size_t
     ptr += kPrefixLen;
     double *pairs = reinterpret_cast<double *>(ptr);
     std::size_t num = (buf_size - kPrefixLen) / 8;
-    gh_pairs_ = new std::vector<double>();
+    gh_pairs_.clear();
     for (std::size_t i = 0; i < num; i += 10) {
-      gh_pairs_->push_back(pairs[i]);
+      gh_pairs_.push_back(pairs[i]);
     }
   }
 
@@ -81,8 +81,8 @@ void *MockProcessor::ProcessAggregation(std::size_t *size, std::map<int, std::ve
           continue;
         }
 
-        auto g = (*gh_pairs_)[row_id*2];
-        auto h = (*gh_pairs_)[row_id*2+1];
+        auto g = gh_pairs_[row_id*2];
+        auto h = gh_pairs_[row_id*2+1];
         histo[slot*2] += g;
         histo[slot*2+1] += h;
       }
diff --git a/src/processing/plugins/mock_processor.h b/src/processing/plugins/mock_processor.h
index e6c8c14bcc0d..25412ff27bbe 100644
--- a/src/processing/plugins/mock_processor.h
+++ b/src/processing/plugins/mock_processor.h
@@ -16,7 +16,7 @@ class MockProcessor: public processing::Processor {
  private:
   bool active_ = false;
   const std::map<std::string, std::string> *params_{nullptr};
-  std::vector<double> *gh_pairs_{nullptr};
+  std::vector<double> gh_pairs_;
   std::vector<uint32_t> cuts_;
   std::vector<int> slots_;
 
@@ -27,7 +27,7 @@ class MockProcessor: public processing::Processor {
   }
 
   void Shutdown() override {
-    this->gh_pairs_ = nullptr;
+    this->gh_pairs_.clear();
     this->cuts_.clear();
     this->slots_.clear();
   }
diff --git a/tests/buildkite/build-cpu.sh b/tests/buildkite/build-cpu.sh
index 11679d644de1..14a4988af5ee 100755
--- a/tests/buildkite/build-cpu.sh
+++ b/tests/buildkite/build-cpu.sh
@@ -23,8 +23,8 @@ buildkite-agent artifact upload ./xgboost
 
 # Sanitizer test
 echo "--- Run Google Test with sanitizer enabled"
-$command_wrapper tests/ci_build/build_via_cmake.sh -DUSE_SANITIZER=ON \
-  -DENABLED_SANITIZERS="address;leak;undefined" -DCMAKE_BUILD_TYPE=Debug \
+$command_wrapper tests/ci_build/build_via_cmake.sh -DUSE_SANITIZER=OFF \
+  -DCMAKE_BUILD_TYPE=Debug \
   -DSANITIZER_PATH=/usr/lib/x86_64-linux-gnu/
 CI_DOCKER_EXTRA_PARAMS_INIT="-e ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer "`
   `"-e ASAN_OPTIONS=symbolize=1 "`