diff --git a/src/pv/watchpid.c b/src/pv/watchpid.c
index fe86dc0..beb0e08 100644
--- a/src/pv/watchpid.c
+++ b/src/pv/watchpid.c
@@ -308,6 +308,7 @@ static int pidfds(pvstate_t state, unsigned int pid, struct proc_fdinfo **fds, i
 		pv_error(state, "%s: alloc failed: %s", _("pid"), strerror(errno));
 		return -1;
 	}
+	memset(fds, 0, size_needed);
 
 	proc_pidinfo(pid, PROC_PIDLISTFDS, 0, *fds, size_needed);