diff --git a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_diff.c b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_diff.c
index 26524e78086c..db132190154c 100644
--- a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_diff.c
+++ b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_diff.c
@@ -472,7 +472,7 @@ differ(void *arg)
 	if (err)
 		return ((void *)-1);
 	if (di->zerr) {
-		ASSERT(di->zerr == EINVAL);
+		ASSERT(di->zerr == EPIPE);
 		(void) snprintf(di->errbuf, sizeof (di->errbuf),
 		    dgettext(TEXT_DOMAIN,
 		    "Internal error: bad data from diff IOCTL"));