[PWGCF] fix possible deref of nullptr error message (#13502)

Author: EmilGorm

PWGCF/GenericFramework/Core/FlowContainer.cxx

@@ -11,6 +11,9 @@
 
 #include "FlowContainer.h"
 
+#include <cstdio>
+#include <vector>
+
 ClassImp(FlowContainer);
 
 FlowContainer::FlowContainer() : TNamed("", ""),
@@ -462,9 +465,11 @@ TH1D* FlowContainer::GetHistCorrXXVsPt(const char* order, double lminmulti, doub
   TProfile* tpf = GetCorrXXVsPt(order, lminmulti, lmaxmulti);
   TH1D* rethist = ProfToHist(tpf);
   TProfile* refflow = GetRefFlowProfile(order, lminmulti, lmaxmulti);
-  refflow->RebinX(refflow->GetNbinsX());
-  rethist->SetBinContent(0, refflow->GetBinContent(1));
-  rethist->SetBinError(0, refflow->GetBinError(1));
+  if (refflow) {
+    refflow->RebinX(refflow->GetNbinsX());
+    rethist->SetBinContent(0, refflow->GetBinContent(1));
+    rethist->SetBinError(0, refflow->GetBinError(1));
+  }
   delete refflow;
   delete tpf;
   return rethist;
@@ -916,7 +921,12 @@ TProfile* FlowContainer::GetRefFlowProfile(const char* order, double m1, double
     delete tempprof;
   }
   delete rhSubset;
-  retpf->RebinX(nBins);
+  if (!retpf) {
+    LOGF(error, "Reference flow profile is null");
+    return nullptr;
+  } else {
+    retpf->RebinX(nBins);
+  }
   return retpf;
 };