From 1a00ef57d9f120b711b6b1193d12ba3789d47ec2 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 5 Sep 2023 17:46:46 +0200 Subject: [PATCH] bpf: task_group_seq_get_next: cleanup the usage of next_thread() 1. find_pid_ns() + get_pid_task() under rcu_read_lock() guarantees that we can safely iterate the task->thread_group list. Even if this task exits right after get_pid_task() (or goto retry) and pid_alive() returns 0. Kill the unnecessary pid_alive() check. 2. next_thread() simply can't return NULL, kill the bogus "if (!next_task)" check. Signed-off-by: Oleg Nesterov Acked-by: "Eric W. Biederman" Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20230905154646.GA24928@redhat.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/task_iter.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index c4ab9d6cdbe9c..4d11251080141 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -75,15 +75,8 @@ static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm return NULL; retry: - if (!pid_alive(task)) { - put_task_struct(task); - return NULL; - } - next_task = next_thread(task); put_task_struct(task); - if (!next_task) - return NULL; saved_tid = *tid; *tid = __task_pid_nr_ns(next_task, PIDTYPE_PID, common->ns); -- 2.30.2