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authorOleg Nesterov <oleg@redhat.com>2023-09-05 17:46:46 +0200
committerAlexei Starovoitov <ast@kernel.org>2023-09-08 08:42:19 -0700
commit1a00ef57d9f120b711b6b1193d12ba3789d47ec2 (patch)
treec36fa91e3f80139c3e82cfd267f6f3ee36940149 /kernel/bpf/task_iter.c
parent35897c3c5264469cbd45e44d23c165a08cfb6b3c (diff)
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 <oleg@redhat.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20230905154646.GA24928@redhat.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/task_iter.c')
-rw-r--r--kernel/bpf/task_iter.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index c4ab9d6cdbe9..4d1125108014 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);