linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	bpf@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>,
	netdev@vger.kernel.org, Tejun Heo <tj@kernel.org>,
	kernel-team@fb.com, cgroups@vger.kernel.org,
	Stanislav Fomichev <sdf@fomichev.me>, Yonghong Song <yhs@fb.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment
Date: Fri, 24 May 2019 14:03:23 -0700	[thread overview]
Message-ID: <20190524210321.tzpt7ilaasaagtou@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20190523194532.2376233-1-guro@fb.com>

On Thu, May 23, 2019 at 12:45:28PM -0700, Roman Gushchin wrote:
> This patchset implements a cgroup bpf auto-detachment functionality:
> bpf programs are detached as soon as possible after removal of the
> cgroup, without waiting for the release of all associated resources.

The idea looks great, but doesn't quite work:

$ ./test_cgroup_attach
#override:PASS
[   66.475219] BUG: sleeping function called from invalid context at ../include/linux/percpu-rwsem.h:34
[   66.476095] in_atomic(): 1, irqs_disabled(): 0, pid: 21, name: ksoftirqd/2
[   66.476706] CPU: 2 PID: 21 Comm: ksoftirqd/2 Not tainted 5.2.0-rc1-00211-g1861420d0162 #1564
[   66.477595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
[   66.478360] Call Trace:
[   66.478591]  dump_stack+0x5b/0x8b
[   66.478892]  ___might_sleep+0x22f/0x290
[   66.479230]  cpus_read_lock+0x18/0x50
[   66.479550]  static_key_slow_dec+0x41/0x70
[   66.479914]  cgroup_bpf_release+0x1a6/0x400
[   66.480285]  percpu_ref_switch_to_atomic_rcu+0x203/0x330
[   66.480754]  rcu_core+0x475/0xcc0
[   66.481047]  ? switch_mm_irqs_off+0x684/0xa40
[   66.481422]  ? rcu_note_context_switch+0x260/0x260
[   66.481842]  __do_softirq+0x1cf/0x5ff
[   66.482174]  ? takeover_tasklets+0x5f0/0x5f0
[   66.482542]  ? smpboot_thread_fn+0xab/0x780
[   66.482911]  run_ksoftirqd+0x1a/0x40
[   66.483225]  smpboot_thread_fn+0x3ad/0x780
[   66.483583]  ? sort_range+0x20/0x20
[   66.483894]  ? __kthread_parkme+0xb0/0x190
[   66.484253]  ? sort_range+0x20/0x20
[   66.484562]  ? sort_range+0x20/0x20
[   66.484878]  kthread+0x2e2/0x3e0
[   66.485166]  ? kthread_create_worker_on_cpu+0xb0/0xb0
[   66.485620]  ret_from_fork+0x1f/0x30

Same test runs fine before the patches.


  parent reply	other threads:[~2019-05-24 21:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23 19:45 [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Roman Gushchin
2019-05-23 19:45 ` [PATCH v3 bpf-next 2/4] selftests/bpf: convert test_cgrp2_attach2 example into kselftest Roman Gushchin
2019-05-23 19:45 ` [PATCH v3 bpf-next 3/4] selftests/bpf: enable all available cgroup v2 controllers Roman Gushchin
2019-05-23 19:45 ` [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test Roman Gushchin
2019-05-23 23:09   ` Yonghong Song
2019-05-23 23:43     ` Roman Gushchin
2019-05-23 23:49     ` Roman Gushchin
2019-05-24 21:03 ` Alexei Starovoitov [this message]
2019-05-24 21:40   ` [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Roman Gushchin

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=20190524210321.tzpt7ilaasaagtou@ast-mbp.dhcp.thefacebook.com \
    --to=alexei.starovoitov@gmail.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=cgroups@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=guro@fb.com \
    --cc=kernel-team@fb.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=sdf@fomichev.me \
    --cc=tj@kernel.org \
    --cc=yhs@fb.com \
    /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).