diff --git a/src/r_plane.c b/src/r_plane.c
index 4dfab96c..1f550aa9 100644
--- a/src/r_plane.c
+++ b/src/r_plane.c
@@ -71,8 +71,8 @@ visplane_t *floorplane, *ceilingplane;
 
 // killough 8/1/98: set static number of openings to be large enough
 // (a static limit is okay in this case and avoids difficulties in r_segs.c)
-static int *openings = NULL;
-int *lastopening; // [FG] 32-bit integer math
+int maxopenings;
+int *openings, *lastopening; // [FG] 32-bit integer math
 
 // Clip values are the solid pixel bounding the range.
 //  floorclip starts out SCREENHEIGHT
@@ -128,7 +128,8 @@ void R_InitPlanesRes(void)
   yslope = Z_Calloc(1, video.height * sizeof(*yslope), PU_RENDERER, NULL);
   distscale = Z_Calloc(1, video.width * sizeof(*distscale), PU_RENDERER, NULL);
 
-  openings = Z_Calloc(1, video.width * video.height * sizeof(*openings), PU_RENDERER, NULL);
+  maxopenings = video.width * video.height;
+  openings = Z_Calloc(1, maxopenings * sizeof(*openings), PU_RENDERER, NULL);
 
   xtoskyangle = linearsky ? linearskyangle : xtoviewangle;
 }
diff --git a/src/r_plane.h b/src/r_plane.h
index 0fb483df..d9b2ab7d 100644
--- a/src/r_plane.h
+++ b/src/r_plane.h
@@ -28,7 +28,8 @@ struct visplane_s;
 #define PL_SKYFLAT (0x80000000)
 
 // Visplane related.
-extern  int *lastopening; // [FG] 32-bit integer math
+extern int maxopenings;
+extern int *openings, *lastopening; // [FG] 32-bit integer math
 
 extern int *floorclip, *ceilingclip; // [FG] 32-bit integer math
 extern fixed_t *yslope, *distscale;
diff --git a/src/r_segs.c b/src/r_segs.c
index 42a2481f..cbd031e2 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -566,6 +566,13 @@ void R_StoreWallRange(const int start, const int stop)
   ds_p->curline = curline;
   rw_stopx = stop+1;
 
+  ptrdiff_t pos = lastopening - openings;
+  size_t need = (rw_stopx - start) * sizeof(*lastopening) + pos;
+  if (need > maxopenings)
+  {
+      return;
+  }
+
   // WiggleFix: add this line, in r_segs.c:R_StoreWallRange,
   // right before calls to R_ScaleFromGlobalAngle
   R_FixWiggle(frontsector);