Initialize bo->vfc along with the rest of the busyobj so panics

work.  (slink's pointer test for bo->vfc is impotent because its bo->vfc[1])

bin/varnishd/cache/cache_busyobj.c

@@ -39,6 +39,7 @@
 #include "cache.h"
 
 #include "hash/hash_slinger.h"
+#include "cache/cache_filter.h"
 
 static struct mempool		*vbopool;
 
@@ -156,6 +157,8 @@ VBO_GetBusyObj(struct worker *wrk, const struct req *req)
 
 	VRTPRIV_init(bo->privs);
 
+	VFP_Setup(bo->vfc);
+
 	return (bo);
 }
 

bin/varnishd/cache/cache_fetch.c

@@ -389,7 +389,6 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
 	} else
 		do_ims = 0;
 
-	VFP_Setup(bo->vfc);
 	bo->vfc->bo = bo;
 	bo->vfc->oc = bo->fetch_objcore;
 	bo->vfc->wrk = bo->wrk;
@@ -776,7 +775,6 @@ vbf_stp_error(struct worker *wrk, struct busyobj *bo)
 
 	assert(wrk->handling == VCL_RET_DELIVER);
 
-	VFP_Setup(bo->vfc);
 	bo->vfc->bo = bo;
 	bo->vfc->wrk = bo->wrk;
 	bo->vfc->oc = bo->fetch_objcore;

bin/varnishd/cache/cache_panic.c

@@ -324,8 +324,7 @@ pan_busyobj(const struct busyobj *bo)
 	pan_ws(bo->ws, 4);
 	VSB_printf(pan_vsp, "  refcnt = %u\n", bo->refcount);
 	VSB_printf(pan_vsp, "  retries = %d\n", bo->retries);
-	if (bo->vfc != NULL)
-		VSB_printf(pan_vsp, "  failed = %d\n", bo->vfc->failed);
+	VSB_printf(pan_vsp, "  failed = %d\n", bo->vfc->failed);
 	VSB_printf(pan_vsp, "  state = %d\n", (int)bo->state);
 #define BO_FLAG(l, r, w, d) if(bo->l) VSB_printf(pan_vsp, "    is_" #l "\n");
 #include "tbl/bo_flags.h"