* Re: [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test
[not found] ` <20190523194532.2376233-5-guro@fb.com>
@ 2019-05-23 23:09 ` Yonghong Song
2019-05-23 23:43 ` Roman Gushchin
2019-05-23 23:49 ` Roman Gushchin
0 siblings, 2 replies; 5+ messages in thread
From: Yonghong Song @ 2019-05-23 23:09 UTC (permalink / raw)
To: Roman Gushchin, Alexei Starovoitov, bpf@vger.kernel.org
Cc: Daniel Borkmann, netdev@vger.kernel.org, Tejun Heo, Kernel Team,
cgroups@vger.kernel.org, Stanislav Fomichev,
linux-kernel@vger.kernel.org
On 5/23/19 12:45 PM, Roman Gushchin wrote:
> Add a kselftest to cover bpf auto-detachment functionality.
> The test creates a cgroup, associates some resources with it,
> attaches a couple of bpf programs and deletes the cgroup.
>
> Then it checks that bpf programs are going away in 5 seconds.
>
> Expected output:
> $ ./test_cgroup_attach
> #override:PASS
> #multi:PASS
> #autodetach:PASS
> test_cgroup_attach:PASS
>
> On a kernel without auto-detaching:
> $ ./test_cgroup_attach
> #override:PASS
> #multi:PASS
> #autodetach:FAIL
> test_cgroup_attach:FAIL
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
Looks good to me. It will be good if you can add test_cgroup_attach
to .gitignore to avoid it shows up in `git status`. With that,
Acked-by: Yonghong Song <yhs@fb.com>
> ---
> .../selftests/bpf/test_cgroup_attach.c | 98 ++++++++++++++++++-
> 1 file changed, 97 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/test_cgroup_attach.c b/tools/testing/selftests/bpf/test_cgroup_attach.c
> index 2d6d57f50e10..7671909ee1cb 100644
> --- a/tools/testing/selftests/bpf/test_cgroup_attach.c
> +++ b/tools/testing/selftests/bpf/test_cgroup_attach.c
> @@ -456,9 +456,105 @@ static int test_multiprog(void)
> return rc;
> }
>
> +static int test_autodetach(void)
> +{
> + __u32 prog_cnt = 4, attach_flags;
> + int allow_prog[2] = {0};
> + __u32 prog_ids[2] = {0};
> + int cg = 0, i, rc = -1;
> + void *ptr = NULL;
> + int attempts;
> +
> + for (i = 0; i < ARRAY_SIZE(allow_prog); i++) {
> + allow_prog[i] = prog_load_cnt(1, 1 << i);
> + if (!allow_prog[i])
> + goto err;
> + }
> +
> + if (setup_cgroup_environment())
> + goto err;
> +
> + /* create a cgroup, attach two programs and remember their ids */
> + cg = create_and_get_cgroup("/cg_autodetach");
> + if (cg < 0)
> + goto err;
> +
> + if (join_cgroup("/cg_autodetach"))
> + goto err;
> +
> + for (i = 0; i < ARRAY_SIZE(allow_prog); i++) {
> + if (bpf_prog_attach(allow_prog[i], cg, BPF_CGROUP_INET_EGRESS,
> + BPF_F_ALLOW_MULTI)) {
> + log_err("Attaching prog[%d] to cg:egress", i);
> + goto err;
> + }
> + }
> +
> + /* make sure that programs are attached and run some traffic */
> + assert(bpf_prog_query(cg, BPF_CGROUP_INET_EGRESS, 0, &attach_flags,
> + prog_ids, &prog_cnt) == 0);
> + assert(system(PING_CMD) == 0);
> +
> + /* allocate some memory (4Mb) to pin the original cgroup */
> + ptr = malloc(4 * (1 << 20));
> + if (!ptr)
> + goto err;
> +
> + /* close programs and cgroup fd */
> + for (i = 0; i < ARRAY_SIZE(allow_prog); i++) {
> + close(allow_prog[i]);
> + allow_prog[i] = 0;
> + }
> +
> + close(cg);
> + cg = 0;
> +
> + /* leave the cgroup and remove it. don't detach programs */
> + cleanup_cgroup_environment();
> +
> + /* wait for the asynchronous auto-detachment.
> + * wait for no more than 5 sec and give up.
> + */
> + for (i = 0; i < ARRAY_SIZE(prog_ids); i++) {
> + for (attempts = 5; attempts >= 0; attempts--) {
> + int fd = bpf_prog_get_fd_by_id(prog_ids[i]);
> +
> + if (fd < 0)
> + break;
> +
> + /* don't leave the fd open */
> + close(fd);
> +
> + if (!attempts)
> + goto err;
> +
> + sleep(1);
> + }
> + }
> +
> + rc = 0;
> +err:
> + for (i = 0; i < ARRAY_SIZE(allow_prog); i++)
> + if (allow_prog[i] > 0)
> + close(allow_prog[i]);
> + if (cg)
> + close(cg);
> + free(ptr);
> + cleanup_cgroup_environment();
> + if (!rc)
> + printf("#autodetach:PASS\n");
> + else
> + printf("#autodetach:FAIL\n");
> + return rc;
> +}
> +
> int main(void)
> {
> - int (*tests[])(void) = {test_foo_bar, test_multiprog};
> + int (*tests[])(void) = {
> + test_foo_bar,
> + test_multiprog,
> + test_autodetach,
> + };
> int errors = 0;
> int i;
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test
2019-05-23 23:09 ` [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test Yonghong Song
@ 2019-05-23 23:43 ` Roman Gushchin
2019-05-23 23:49 ` Roman Gushchin
1 sibling, 0 replies; 5+ messages in thread
From: Roman Gushchin @ 2019-05-23 23:43 UTC (permalink / raw)
To: Yonghong Song
Cc: Alexei Starovoitov, bpf@vger.kernel.org, Daniel Borkmann,
netdev@vger.kernel.org, Tejun Heo, Kernel Team,
cgroups@vger.kernel.org, Stanislav Fomichev,
linux-kernel@vger.kernel.org
On Thu, May 23, 2019 at 04:09:30PM -0700, Yonghong Song wrote:
>
>
> On 5/23/19 12:45 PM, Roman Gushchin wrote:
> > Add a kselftest to cover bpf auto-detachment functionality.
> > The test creates a cgroup, associates some resources with it,
> > attaches a couple of bpf programs and deletes the cgroup.
> >
> > Then it checks that bpf programs are going away in 5 seconds.
> >
> > Expected output:
> > $ ./test_cgroup_attach
> > #override:PASS
> > #multi:PASS
> > #autodetach:PASS
> > test_cgroup_attach:PASS
> >
> > On a kernel without auto-detaching:
> > $ ./test_cgroup_attach
> > #override:PASS
> > #multi:PASS
> > #autodetach:FAIL
> > test_cgroup_attach:FAIL
> >
> > Signed-off-by: Roman Gushchin <guro@fb.com>
>
> Looks good to me. It will be good if you can add test_cgroup_attach
> to .gitignore to avoid it shows up in `git status`. With that,
I don't think it deserves a new version, I'll prepare a separate patch
for it.
>
> Acked-by: Yonghong Song <yhs@fb.com>
Thank you for the review!
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test
2019-05-23 23:09 ` [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test Yonghong Song
2019-05-23 23:43 ` Roman Gushchin
@ 2019-05-23 23:49 ` Roman Gushchin
1 sibling, 0 replies; 5+ messages in thread
From: Roman Gushchin @ 2019-05-23 23:49 UTC (permalink / raw)
To: Yonghong Song
Cc: Alexei Starovoitov, bpf@vger.kernel.org, Daniel Borkmann,
netdev@vger.kernel.org, Tejun Heo, Kernel Team,
cgroups@vger.kernel.org, Stanislav Fomichev,
linux-kernel@vger.kernel.org
On Thu, May 23, 2019 at 04:09:30PM -0700, Yonghong Song wrote:
>
>
> On 5/23/19 12:45 PM, Roman Gushchin wrote:
> > Add a kselftest to cover bpf auto-detachment functionality.
> > The test creates a cgroup, associates some resources with it,
> > attaches a couple of bpf programs and deletes the cgroup.
> >
> > Then it checks that bpf programs are going away in 5 seconds.
> >
> > Expected output:
> > $ ./test_cgroup_attach
> > #override:PASS
> > #multi:PASS
> > #autodetach:PASS
> > test_cgroup_attach:PASS
> >
> > On a kernel without auto-detaching:
> > $ ./test_cgroup_attach
> > #override:PASS
> > #multi:PASS
> > #autodetach:FAIL
> > test_cgroup_attach:FAIL
> >
> > Signed-off-by: Roman Gushchin <guro@fb.com>
>
> Looks good to me. It will be good if you can add test_cgroup_attach
> to .gitignore to avoid it shows up in `git status`. With that,
>
Here it is!
Thanks!
---
From 150fb4db7ab37f0e8b6482386e8830f3d11b64e1 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <guro@fb.com>
Date: Thu, 23 May 2019 16:46:58 -0700
Subject: [PATCH bpf-next] selftests/bpf: add test_cgroup_attach to .gitignore
Add test_cgroup_attach binary to .gitignore.
Signed-off-by: Roman Gushchin <guro@fb.com>
---
tools/testing/selftests/bpf/.gitignore | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index dd5d69529382..86a546e5e4db 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -22,6 +22,7 @@ test_lirc_mode2_user
get_cgroup_id_user
test_skb_cgroup_id_user
test_socket_cookie
+test_cgroup_attach
test_cgroup_storage
test_select_reuseport
test_flow_dissector
--
2.20.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment
[not found] <20190523194532.2376233-1-guro@fb.com>
[not found] ` <20190523194532.2376233-5-guro@fb.com>
@ 2019-05-24 21:03 ` Alexei Starovoitov
2019-05-24 21:40 ` Roman Gushchin
1 sibling, 1 reply; 5+ messages in thread
From: Alexei Starovoitov @ 2019-05-24 21:03 UTC (permalink / raw)
To: Roman Gushchin
Cc: Alexei Starovoitov, bpf, Daniel Borkmann, netdev, Tejun Heo,
kernel-team, cgroups, Stanislav Fomichev, Yonghong Song,
linux-kernel
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.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment
2019-05-24 21:03 ` [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Alexei Starovoitov
@ 2019-05-24 21:40 ` Roman Gushchin
0 siblings, 0 replies; 5+ messages in thread
From: Roman Gushchin @ 2019-05-24 21:40 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Alexei Starovoitov, bpf@vger.kernel.org, Daniel Borkmann,
netdev@vger.kernel.org, Tejun Heo, Kernel Team,
cgroups@vger.kernel.org, Stanislav Fomichev, Yonghong Song,
linux-kernel@vger.kernel.org
On Fri, May 24, 2019 at 02:03:23PM -0700, Alexei Starovoitov wrote:
> 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.
>
Ouch, static_branch_dec() might block, so it's not possible to call it from
percpu ref counter release callback. It's not what I expected, tbh.
Good catch, thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread
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[not found] <20190523194532.2376233-1-guro@fb.com>
[not found] ` <20190523194532.2376233-5-guro@fb.com>
2019-05-23 23:09 ` [PATCH v3 bpf-next 4/4] selftests/bpf: add auto-detach test Yonghong Song
2019-05-23 23:43 ` Roman Gushchin
2019-05-23 23:49 ` Roman Gushchin
2019-05-24 21:03 ` [PATCH v3 bpf-next 0/4] cgroup bpf auto-detachment Alexei Starovoitov
2019-05-24 21:40 ` Roman Gushchin
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