diff --git a/src/hlua.c b/src/hlua.c
index 37fce89..d0eb7f5 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -2770,6 +2770,9 @@
 	memset(&smp, 0, sizeof(smp));
 
 	/* Run the sample fetch process. */
+	smp.px = hsmp->p;
+	smp.sess = hsmp->s->sess;
+	smp.strm = hsmp->s;
 	if (!f->process(hsmp->p, hsmp->s->sess, hsmp->s, 0, args, &smp, f->kw, f->private)) {
 		if (hsmp->stringsafe)
 			lua_pushstring(L, "");
@@ -2888,6 +2891,9 @@
 	}
 
 	/* Run the sample conversion process. */
+	smp.px = hsmp->p;
+	smp.sess = hsmp->s->sess;
+	smp.strm = hsmp->s;
 	if (!conv->process(hsmp->s, args, &smp, conv->private)) {
 		if (hsmp->stringsafe)
 			lua_pushstring(L, "");
diff --git a/src/sample.c b/src/sample.c
index 77192be..53c9d0d 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -1033,6 +1033,9 @@
 		memset(p, 0, sizeof(*p));
 	}
 
+	p->px   = px;
+	p->sess = sess;
+	p->strm = strm;
 	if (!expr->fetch->process(px, sess, strm, opt, expr->arg_p, p, expr->fetch->kw, expr->fetch->private))
 		return NULL;