Commit e60572b8 authored Aug 18, 2020 by Yonghong Song Committed by Alexei Starovoitov Aug 18, 2020

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: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei 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;

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