Netdev Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Yonghong Song <yhs@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
	Rik van Riel <riel@surriel.com>
Subject: [PATCH bpf v2 2/3] bpf: avoid visit same object multiple times
Date: Tue, 18 Aug 2020 15:23:10 -0700	[thread overview]
Message-ID: <20200818222310.2181500-1-yhs@fb.com> (raw)
In-Reply-To: <20200818222309.2181236-1-yhs@fb.com>

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().

Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Yonghong Song <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;
-- 
2.24.1


  parent reply	other threads:[~2020-08-18 22:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18 22:23 [PATCH bpf v2 0/3] bpf: two fixes for bpf iterators Yonghong Song
2020-08-18 22:23 ` [PATCH bpf v2 1/3] bpf: fix a rcu_sched stall issue with bpf task/task_file iterator Yonghong Song
2020-08-19  0:05   ` Alexei Starovoitov
2020-08-19  0:30     ` Yonghong Song
2020-08-19  0:49       ` Alexei Starovoitov
2020-08-18 22:23 ` Yonghong Song [this message]
2020-08-18 22:23 ` [PATCH bpf v2 3/3] bpftool: handle EAGAIN error code properly in pids collection Yonghong Song
2020-08-18 22:30   ` Andrii Nakryiko
2020-08-18 22:28 ` [PATCH bpf v2 0/3] bpf: two fixes for bpf iterators Yonghong Song

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200818222310.2181500-1-yhs@fb.com \
    --to=yhs@fb.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    --cc=riel@surriel.com \
    --subject='Re: [PATCH bpf v2 2/3] bpf: avoid visit same object multiple times' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).