From eeff6aa06c09d3335fc0dfc6fc354e918ab6cad1 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Sat, 1 Oct 2022 13:34:55 -0400
Subject: [PATCH] make sure to always look up the region to avoid null pointer
 dereference

---
 src/compute_chunk_atom.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/compute_chunk_atom.cpp b/src/compute_chunk_atom.cpp
index ccd5da433f..013efb8c50 100644
--- a/src/compute_chunk_atom.cpp
+++ b/src/compute_chunk_atom.cpp
@@ -906,7 +906,11 @@ void ComputeChunkAtom::assign_chunk_ids()
 
   // update region if necessary
 
-  if (regionflag) region->prematch();
+  if (regionflag) {
+    region = domain->get_region_by_id(idregion);
+    if (!region) error->all(FLERR, "Region {} for compute chunk/atom does not exist", idregion);
+    region->prematch();
+  }
 
   // exclude = 1 if atom is not assigned to a chunk
   // exclude atoms not in group or not in optional region