diff --git a/src/afs/afs_pioctl.c b/src/afs/afs_pioctl.c
index e9a84e3d2f..89a56b9760 100644
--- a/src/afs/afs_pioctl.c
+++ b/src/afs/afs_pioctl.c
@@ -62,6 +62,11 @@ afs_pd_alloc(struct afs_pdata *apd, size_t size)
     if (apd->ptr == NULL)
 	return ENOMEM;
 
+    if (size > AFS_LRALLOCSIZ)
+	memset(apd->ptr, 0, size + 1);
+    else
+	memset(apd->ptr, 0, AFS_LRALLOCSIZ);
+
     apd->remaining = size;
 
     return 0;