bpf.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: John Fastabend <john.fastabend@gmail.com>
To: Andrii Nakryiko <andriin@fb.com>,
	bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
	daniel@iogearbox.net
Cc: andrii.nakryiko@gmail.com, kernel-team@fb.com,
	Andrii Nakryiko <andriin@fb.com>
Subject: RE: [PATCH bpf-next 1/2] libbpf: stop enforcing kern_version, populate it for users
Date: Fri, 04 Oct 2019 07:05:18 -0700	[thread overview]
Message-ID: <5d97519e9e7f3_4e6d2b183260e5bcbf@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20191004030058.2248514-2-andriin@fb.com>

Andrii Nakryiko wrote:
> Kernel version enforcement for kprobes/kretprobes was removed from
> 5.0 kernel in 6c4fc209fcf9 ("bpf: remove useless version check for prog load").
> Since then, BPF programs were specifying SEC("version") just to please
> libbpf. We should stop enforcing this in libbpf, if even kernel doesn't
> care. Furthermore, libbpf now will pre-populate current kernel version
> of the host system, in case we are still running on old kernel.
> 
> This patch also removes __bpf_object__open_xattr from libbpf.h, as
> nothing in libbpf is relying on having it in that header. That function
> was never exported as LIBBPF_API and even name suggests its internal
> version. So this should be safe to remove, as it doesn't break ABI.
> 
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> ---
>  tools/lib/bpf/libbpf.c                        | 79 ++++++-------------
>  tools/lib/bpf/libbpf.h                        |  2 -
>  .../selftests/bpf/progs/test_attach_probe.c   |  1 -
>  .../bpf/progs/test_get_stack_rawtp.c          |  1 -
>  .../selftests/bpf/progs/test_perf_buffer.c    |  1 -
>  .../selftests/bpf/progs/test_stacktrace_map.c |  1 -
>  6 files changed, 22 insertions(+), 63 deletions(-)

[...]

>  static struct bpf_object *
> -__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
> -		   bool needs_kver, int flags)
> +__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
> +		   int flags)
>  {
>  	struct bpf_object *obj;
>  	int err;
> @@ -3617,7 +3585,6 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
>  	CHECK_ERR(bpf_object__probe_caps(obj), err, out);
>  	CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out);

If we are not going to validate the section should we also skip collect'ing it?

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e0276520171b..22a458cd602c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1567,12 +1567,6 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
                                                       data->d_size);
                        if (err)
                                return err;
-               } else if (strcmp(name, "version") == 0) {
-                       err = bpf_object__init_kversion(obj,
-                                                       data->d_buf,
-                                                       data->d_size);
-                       if (err)
-                               return err;
                } else if (strcmp(name, "maps") == 0) {
                        obj->efile.maps_shndx = idx;
                } else if (strcmp(name, MAPS_ELF_SEC) == 0) {


>  	CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
> -	CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out);
>  
>  	bpf_object__elf_finish(obj);
>  	return obj;
> @@ -3626,8 +3593,8 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
>  	return ERR_PTR(err);
>  }

  reply	other threads:[~2019-10-04 14:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-04  3:00 [PATCH bpf-next 0/2] Add new-style bpf_object__open APIs Andrii Nakryiko
2019-10-04  3:00 ` [PATCH bpf-next 1/2] libbpf: stop enforcing kern_version, populate it for users Andrii Nakryiko
2019-10-04 14:05   ` John Fastabend [this message]
2019-10-04 14:32     ` Andrii Nakryiko
2019-10-04 14:36       ` Alexei Starovoitov
2019-10-04 14:55         ` John Fastabend
2019-10-04 15:07         ` Andrii Nakryiko
2019-10-04 15:59           ` John Fastabend
2019-10-18 14:49             ` John Fastabend
2019-10-04  3:00 ` [PATCH bpf-next 2/2] libbpf: add bpf_object__open_{file,mem} w/ extensible opts Andrii Nakryiko

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=5d97519e9e7f3_4e6d2b183260e5bcbf@john-XPS-13-9370.notmuch \
    --to=john.fastabend@gmail.com \
    --cc=andrii.nakryiko@gmail.com \
    --cc=andriin@fb.com \
    --cc=ast@fb.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    --subject='RE: [PATCH bpf-next 1/2] libbpf: stop enforcing kern_version, populate it for users' \
    /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).