From e60572b8d4c39572be6857d1ec91fdf979f8775f Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 18 Aug 2020 15:23:10 -0700 Subject: 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 Signed-off-by: Alexei Starovoitov Cc: Rik van Riel Link: https://lore.kernel.org/bpf/20200818222310.2181500-1-yhs@fb.com --- kernel/bpf/task_iter.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index f21b5e1e4540..99af4cea1102 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -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; -- cgit v1.2.3