diff --git a/bin/varnishd/cache/cache_vcl.c b/bin/varnishd/cache/cache_vcl.c
index 055c84107c..41ae74743d 100644
--- a/bin/varnishd/cache/cache_vcl.c
+++ b/bin/varnishd/cache/cache_vcl.c
@@ -299,6 +299,11 @@ VCL_Open(const char *fn, struct vsb *msg)
 	AN(fn);
 	AN(msg);
 
+#ifdef RTLD_NOLOAD
+	/* Detect bogus caching by dlopen(3) */
+	dlh = dlopen(fn, RTLD_NOW | RTLD_NOLOAD);
+	AZ(dlh);
+#endif
 	dlh = dlopen(fn, RTLD_NOW | RTLD_LOCAL);
 	if (dlh == NULL) {
 		VSB_printf(msg, "Could not load compiled VCL.\n");
diff --git a/bin/varnishd/mgt/mgt_vcc.c b/bin/varnishd/mgt/mgt_vcc.c
index d7f3565b14..ca8ae94798 100644
--- a/bin/varnishd/mgt/mgt_vcc.c
+++ b/bin/varnishd/mgt/mgt_vcc.c
@@ -47,6 +47,7 @@
 #include "vcli_serve.h"
 #include "vfil.h"
 #include "vsub.h"
+#include "vtim.h"
 
 struct vcc_priv {
 	unsigned	magic;
@@ -272,7 +273,39 @@ mgt_VccCompile(struct cli *cli, const char *vclname, const char *vclsrc,
 	vp.vclsrc = vclsrc;
 	vp.vclsrcfile = vclsrcfile;
 
-	VSB_printf(sb, "vcl_%s", vclname);
+	/*
+	 * The subdirectory must have a unique name to 100% certain evade
+	 * the refcounting semantics of dlopen(3).
+	 *
+	 * Bad implementations of dlopen(3) think the shlib you are opening
+	 * is the same, if the filename is the same as one already opened.
+	 *
+	 * Sensible implementations do a stat(2) and requires st_ino and
+	 * st_dev to also match.
+	 *
+	 * A correct implementation would run on filesystems which tickle
+	 * st_gen, and also insist that be the identical, before declaring
+	 * a match.
+	 *
+	 * Since no correct implementations are known to exist, we are subject
+	 * to really interesting races if you do something like:
+	 *
+	 *	(running on 'boot' vcl)
+	 *	vcl.load foo /foo.vcl
+	 *	vcl.use foo
+	 *	few/slow requests
+	 *	vcl.use boot
+	 *	vcl.discard foo
+	 *	vcl.load foo /foo.vcl	// dlopen(3) says "same-same"
+	 *	vcl.use foo
+	 *
+	 * Because discard of the first 'foo' lingers on non-zero reference
+	 * count, and when it finally runs, it trashes the second 'foo' because
+	 * dlopen(3) decided they were really the same thing.
+	 *
+	 * The Best way to reproduce ths is to have regexps in the VCL.
+	 */
+	VSB_printf(sb, "vcl_%s.%.9f", vclname, VTIM_real());
 	AZ(VSB_finish(sb));
 	vp.dir = strdup(VSB_data(sb));
 	AN(vp.dir);
diff --git a/bin/varnishd/mgt/mgt_vcl.c b/bin/varnishd/mgt/mgt_vcl.c
index d9cd0438f7..d0843537c5 100644
--- a/bin/varnishd/mgt/mgt_vcl.c
+++ b/bin/varnishd/mgt/mgt_vcl.c
@@ -92,16 +92,25 @@ mgt_vcl_add(const char *name, const char *libfile, const char *state)
 static void
 mgt_vcl_del(struct vclprog *vp)
 {
-	char dn[256];
+	char *p;
 
 	VTAILQ_REMOVE(&vclhead, vp, list);
-	if (strcmp(vp->state, VCL_STATE_LABEL))
-		XXXAZ(unlink(vp->fname));
-	bprintf(dn, "vcl_%s", vp->name);
-	VJ_master(JAIL_MASTER_FILE);
-	(void)rmdir(dn);		// compiler droppings, eg gcov
-	VJ_master(JAIL_MASTER_LOW);
-	free(vp->fname);
+	if (strcmp(vp->state, VCL_STATE_LABEL)) {
+		AZ(unlink(vp->fname));
+		p = strrchr(vp->fname, '/');
+		AN(p);
+		*p = '\0';
+		VJ_master(JAIL_MASTER_FILE);
+		/*
+		 * This will fail if any files are dropped next to the library
+		 * without us knowing.  This happens for instance with GCOV.
+		 * Assume developers know how to clean up after themselves
+		 * (or alternatively:  How to run out of disk space).
+		 */
+		(void)rmdir(vp->fname);
+		VJ_master(JAIL_MASTER_LOW);
+		free(vp->fname);
+	}
 	free(vp->name);
 	free(vp);
 }