From: Chuyi Zhou <zhouchuyi@bytedance.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@kernel.org>,
Tejun Heo <tj@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RESEND PATCH bpf-next v6 8/8] selftests/bpf: Add tests for open-coded task and css iter
Date: Fri, 20 Oct 2023 08:30:03 +0800 [thread overview]
Message-ID: <92e8f98e-466d-45be-aa0a-35e02419a5c0@bytedance.com> (raw)
In-Reply-To: <CAADnVQKafk_junRyE=-FVAik4hjTRDtThymYGEL8hGTuYoOGpA@mail.gmail.com>
Hello,
在 2023/10/20 08:03, Alexei Starovoitov 写道:
> On Tue, Oct 17, 2023 at 11:18 PM Chuyi Zhou <zhouchuyi@bytedance.com> wrote:
>>
>> +
>> +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
>> +__failure __msg("css_task_iter is only allowed in bpf_lsm and bpf iter-s")
>> +int BPF_PROG(iter_css_task_for_each)
>> +{
>> + u64 cg_id = bpf_get_current_cgroup_id();
>> + struct cgroup *cgrp = bpf_cgroup_from_id(cg_id);
>> + struct cgroup_subsys_state *css;
>> + struct task_struct *task;
>> +
>> + if (cgrp == NULL)
>> + return 0;
>> + css = &cgrp->self;
>> +
>> + bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
>> +
>> + }
>> + bpf_cgroup_release(cgrp);
>> + return 0;
>> +}
>
> I think we should relax allowlist in patch 2 further.
> Any sleepable is safe.
> Allowlist is needed to avoid dead locking on css_set_lock.
> Any lsm and any iter (even non-sleepable) and any sleepable
> seems to be safe.
>
> Then the above test would need s/fentry.s/fentry/ to stay relevant.
>
> I would also add:
>
> SEC("iter/cgroup")
> int cgroup_id_printer(struct bpf_iter__cgroup *ctx)
> {
> struct seq_file *seq = ctx->meta->seq;
> struct cgroup *cgrp = ctx->cgroup;
>
> /* epilogue */
> if (cgrp == NULL) ..
>
> bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
> BPF_SEQ_PRINTF(); // something about task
> }
>
> To demonstrate how new kfunc iter can be combined with cgroup iter and
> it won't deadlock, though cgroup iter is not sleepable.
>
OK.
> I've applied the current set. Pls send a follow up. Thanks
I would try to send a follow up patch next week.
Thank.
next prev parent reply other threads:[~2023-10-20 0:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-18 6:17 [RESEND PATCH bpf-next v6 0/8] Add Open-coded task, css_task and css iters Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 2/8] bpf: Introduce css_task open-coded iterator kfuncs Chuyi Zhou
2023-10-29 17:09 ` Guenter Roeck
2023-10-30 2:32 ` Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 3/8] bpf: Introduce task open coded " Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 4/8] bpf: Introduce css open-coded " Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 5/8] bpf: teach the verifier to enforce css_iter and task_iter in RCU CS Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 6/8] bpf: Let bpf_iter_task_new accept null task ptr Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 7/8] selftests/bpf: rename bpf_iter_task.c to bpf_iter_tasks.c Chuyi Zhou
2023-10-18 6:17 ` [RESEND PATCH bpf-next v6 8/8] selftests/bpf: Add tests for open-coded task and css iter Chuyi Zhou
2023-10-20 0:03 ` Alexei Starovoitov
2023-10-20 0:30 ` Chuyi Zhou [this message]
2023-10-20 14:46 ` Chuyi Zhou
2023-10-18 6:21 ` [RESEND PATCH bpf-next v6 0/8] Add Open-coded task, css_task and css iters Chuyi Zhou
2023-10-20 0:10 ` patchwork-bot+netdevbpf
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=92e8f98e-466d-45be-aa0a-35e02419a5c0@bytedance.com \
--to=zhouchuyi@bytedance.com \
--cc=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.lau@kernel.org \
--cc=tj@kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).