Commit e60572b8 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Avoid visit same object multiple times 



Currently when traversing all tasks, the next tid
is always increased by one. This may result in
visiting the same task multiple times in a
pid namespace.

This patch fixed the issue by seting the next
tid as pid_nr_ns(pid, ns) + 1, similar to
funciton next_tgid().

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/bpf/20200818222310.2181500-1-yhs@fb.com
parent e679654a

kernel/bpf/task_iter.c

+2 −1
Original line number Diff line number Diff line
@@ -29,8 +29,9 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns, 


	rcu_read_lock();

retry:

	pid = idr_get_next(&ns->idr, tid);

	pid = find_ge_pid(*tid, ns);

	if (pid) {

		*tid = pid_nr_ns(pid, ns);

		task = get_pid_task(pid, PIDTYPE_PID);

		if (!task) {

			++*tid;