proc: Use PIDTYPE_TGID in next_tgid (3147d8aa) · Commits · 戴 / test

Combine the pid_task and thes test has_group_leader_pid into a single dereference by using pid_task(PIDTYPE_TGID). This makes the code simpler and proof against needing to even think about any shenanigans that de_thread might get up to. Acked-by:

Oleg Nesterov <oleg@redhat.com> Signed-off-by:

"Eric W. Biederman" <ebiederm@xmission.com>

fs/proc/base.c

+2 −14

Original line number	Diff line number	Diff line
		@@ -3359,20 +3359,8 @@ retry:
		pid = find_ge_pid(iter.tgid, ns);
		if (pid) {
		iter.tgid = pid_nr_ns(pid, ns);
		iter.task = pid_task(pid, PIDTYPE_PID);
		/* What we to know is if the pid we have find is the
		* pid of a thread_group_leader. Testing for task
		* being a thread_group_leader is the obvious thing
		* todo but there is a window when it fails, due to
		* the pid transfer logic in de_thread.
		*
		* So we perform the straight forward test of seeing
		* if the pid we have found is the pid of a thread
		* group leader, and don't worry if the task we have
		* found doesn't happen to be a thread group leader.
		* As we don't care in the case of readdir.
		*/
		if (!iter.task \|\| !has_group_leader_pid(iter.task)) {
		iter.task = pid_task(pid, PIDTYPE_TGID);
		if (!iter.task) {
		iter.tgid += 1;
		goto retry;
		}

Admin message