* [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag
@ 2020-01-08 1:40 Andrey Ignatov
2020-01-08 16:31 ` Song Liu
0 siblings, 1 reply; 4+ messages in thread
From: Andrey Ignatov @ 2020-01-08 1:40 UTC (permalink / raw)
To: bpf; +Cc: Andrey Ignatov, ast, daniel, kernel-team
Document BPF_F_QUERY_EFFECTIVE flag, mostly to clarify how it affects
attach_flags what may not be obvious and what may lead to confision.
Specifically attach_flags is returned only for target_fd but if programs
are inherited from an ancestor cgroup then returned attach_flags for
current cgroup may be confusing. For example, two effective programs of
same attach_type can be returned but w/o BPF_F_ALLOW_MULTI in
attach_flags.
Simple repro:
# bpftool c s /sys/fs/cgroup/path/to/task
ID AttachType AttachFlags Name
# bpftool c s /sys/fs/cgroup/path/to/task effective
ID AttachType AttachFlags Name
95043 ingress tw_ipt_ingress
95048 ingress tw_ingress
Signed-off-by: Andrey Ignatov <rdna@fb.com>
---
include/uapi/linux/bpf.h | 7 ++++++-
tools/include/uapi/linux/bpf.h | 7 ++++++-
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7df436da542d..dc4b8a2d2a86 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -357,7 +357,12 @@ enum bpf_attach_type {
/* Enable memory-mapping BPF map */
#define BPF_F_MMAPABLE (1U << 10)
-/* flags for BPF_PROG_QUERY */
+/* Flags for BPF_PROG_QUERY. */
+
+/* Query effective (directly attached + inherited from ancestor cgroups)
+ * programs that will be executed for events within a cgroup.
+ * attach_flags with this flag are returned only for directly attached programs.
+ */
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
enum bpf_stack_build_id_status {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7df436da542d..dc4b8a2d2a86 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -357,7 +357,12 @@ enum bpf_attach_type {
/* Enable memory-mapping BPF map */
#define BPF_F_MMAPABLE (1U << 10)
-/* flags for BPF_PROG_QUERY */
+/* Flags for BPF_PROG_QUERY. */
+
+/* Query effective (directly attached + inherited from ancestor cgroups)
+ * programs that will be executed for events within a cgroup.
+ * attach_flags with this flag are returned only for directly attached programs.
+ */
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
enum bpf_stack_build_id_status {
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag
2020-01-08 1:40 [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag Andrey Ignatov
@ 2020-01-08 16:31 ` Song Liu
2020-01-08 17:19 ` Andrey Ignatov
0 siblings, 1 reply; 4+ messages in thread
From: Song Liu @ 2020-01-08 16:31 UTC (permalink / raw)
To: Andrey Ignatov; +Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Kernel Team
> On Jan 7, 2020, at 5:40 PM, Andrey Ignatov <rdna@fb.com> wrote:
>
> Document BPF_F_QUERY_EFFECTIVE flag, mostly to clarify how it affects
> attach_flags what may not be obvious and what may lead to confision.
>
> Specifically attach_flags is returned only for target_fd but if programs
> are inherited from an ancestor cgroup then returned attach_flags for
> current cgroup may be confusing. For example, two effective programs of
> same attach_type can be returned but w/o BPF_F_ALLOW_MULTI in
> attach_flags.
>
> Simple repro:
> # bpftool c s /sys/fs/cgroup/path/to/task
> ID AttachType AttachFlags Name
> # bpftool c s /sys/fs/cgroup/path/to/task effective
> ID AttachType AttachFlags Name
> 95043 ingress tw_ipt_ingress
> 95048 ingress tw_ingress
>
> Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
With some nit below.
> ---
> include/uapi/linux/bpf.h | 7 ++++++-
> tools/include/uapi/linux/bpf.h | 7 ++++++-
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 7df436da542d..dc4b8a2d2a86 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -357,7 +357,12 @@ enum bpf_attach_type {
> /* Enable memory-mapping BPF map */
> #define BPF_F_MMAPABLE (1U << 10)
>
> -/* flags for BPF_PROG_QUERY */
> +/* Flags for BPF_PROG_QUERY. */
> +
> +/* Query effective (directly attached + inherited from ancestor cgroups)
> + * programs that will be executed for events within a cgroup.
> + * attach_flags with this flag are returned only for directly attached programs.
This line is more than 75 byte long, I guess ./scripts/checkpatch.pl would
complain about it?
Thanks,
Song
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag
2020-01-08 16:31 ` Song Liu
@ 2020-01-08 17:19 ` Andrey Ignatov
2020-01-09 17:41 ` Alexei Starovoitov
0 siblings, 1 reply; 4+ messages in thread
From: Andrey Ignatov @ 2020-01-08 17:19 UTC (permalink / raw)
To: Song Liu; +Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Kernel Team
Song Liu <songliubraving@fb.com> [Wed, 2020-01-08 08:31 -0800]:
[...]
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 7df436da542d..dc4b8a2d2a86 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -357,7 +357,12 @@ enum bpf_attach_type {
> > /* Enable memory-mapping BPF map */
> > #define BPF_F_MMAPABLE (1U << 10)
> >
> > -/* flags for BPF_PROG_QUERY */
> > +/* Flags for BPF_PROG_QUERY. */
> > +
> > +/* Query effective (directly attached + inherited from ancestor cgroups)
> > + * programs that will be executed for events within a cgroup.
> > + * attach_flags with this flag are returned only for directly attached programs.
>
> This line is more than 75 byte long, I guess ./scripts/checkpatch.pl would
> complain about it?
I run checkpatch.pl before sending it but it didn't complain:
% scripts/checkpatch.pl p/0001-bpf-Document-BPF_F_QUERY_EFFECTIVE-flag.patch
total: 0 errors, 0 warnings, 26 lines checked
p/0001-bpf-Document-BPF_F_QUERY_EFFECTIVE-flag.patch has no obvious style problems and is ready for submission.
I haven't debugged why, but this header has plenty of lines like this:
% awk 'length($0) >= 75' include/uapi/linux/bpf.h | wc -l
74
--
Andrey Ignatov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag
2020-01-08 17:19 ` Andrey Ignatov
@ 2020-01-09 17:41 ` Alexei Starovoitov
0 siblings, 0 replies; 4+ messages in thread
From: Alexei Starovoitov @ 2020-01-09 17:41 UTC (permalink / raw)
To: Andrey Ignatov
Cc: Song Liu, bpf, Alexei Starovoitov, Daniel Borkmann, Kernel Team
On Wed, Jan 8, 2020 at 9:20 AM Andrey Ignatov <rdna@fb.com> wrote:
>
> Song Liu <songliubraving@fb.com> [Wed, 2020-01-08 08:31 -0800]:
> [...]
> > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > > index 7df436da542d..dc4b8a2d2a86 100644
> > > --- a/include/uapi/linux/bpf.h
> > > +++ b/include/uapi/linux/bpf.h
> > > @@ -357,7 +357,12 @@ enum bpf_attach_type {
> > > /* Enable memory-mapping BPF map */
> > > #define BPF_F_MMAPABLE (1U << 10)
> > >
> > > -/* flags for BPF_PROG_QUERY */
> > > +/* Flags for BPF_PROG_QUERY. */
> > > +
> > > +/* Query effective (directly attached + inherited from ancestor cgroups)
> > > + * programs that will be executed for events within a cgroup.
> > > + * attach_flags with this flag are returned only for directly attached programs.
> >
> > This line is more than 75 byte long, I guess ./scripts/checkpatch.pl would
> > complain about it?
>
> I run checkpatch.pl before sending it but it didn't complain:
>
> % scripts/checkpatch.pl p/0001-bpf-Document-BPF_F_QUERY_EFFECTIVE-flag.patch
> total: 0 errors, 0 warnings, 26 lines checked
>
> p/0001-bpf-Document-BPF_F_QUERY_EFFECTIVE-flag.patch has no obvious style problems and is ready for submission.
>
> I haven't debugged why, but this header has plenty of lines like this:
>
> % awk 'length($0) >= 75' include/uapi/linux/bpf.h | wc -l
> 74
Applied. Thanks
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-01-08 1:40 [PATCH bpf-next] bpf: Document BPF_F_QUERY_EFFECTIVE flag Andrey Ignatov
2020-01-08 16:31 ` Song Liu
2020-01-08 17:19 ` Andrey Ignatov
2020-01-09 17:41 ` Alexei Starovoitov
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