From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AEB4C433F5 for ; Thu, 9 Sep 2021 18:08:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43C186113A for ; Thu, 9 Sep 2021 18:08:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243284AbhIISJg (ORCPT ); Thu, 9 Sep 2021 14:09:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231431AbhIISJg (ORCPT ); Thu, 9 Sep 2021 14:09:36 -0400 Received: from mail-yb1-xb2f.google.com (mail-yb1-xb2f.google.com [IPv6:2607:f8b0:4864:20::b2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 574D4C061574 for ; Thu, 9 Sep 2021 11:08:26 -0700 (PDT) Received: by mail-yb1-xb2f.google.com with SMTP id q70so5624455ybg.11 for ; Thu, 09 Sep 2021 11:08:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dLP20YnxrsQDJ3m1Fbq0OVBArGUIGfPCQaTrJ+L2sdg=; b=jPOhzq0IIk7rVSwubmthONfsNpvNbOCYLhg5ivqSZeI4zPMPemX14vj+s1rZhzcnkp Ybnyfo8L8CF7BQ4VIUSqsV6hvR4I2zge6Q1cJg3wPxaQUAFjgA/wrdNJBtb4fPIKcH3F bhoqcX7mqBAH+48+HHptxo774d7UviSILlJ7SBMmfverpJHCB6Dl82Qdp8YfRMZyG+pF AtkrXBjDb/WgWtgDgDdNM5DYt9i55YNBeCAnMA0lLK2s7bC0pmpq506LVeyCePRbVnX5 uXQ2nCqGYsF4PjWLij4qDoByHzvfZMAXmTEySuLcfOXJtjkbO/bdMA8C9Dtb51gIVB4l /asg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dLP20YnxrsQDJ3m1Fbq0OVBArGUIGfPCQaTrJ+L2sdg=; b=1f+W/PYMG8tlehNJxmKLJGFH/jl9jraKg+X+YQggndol3fpEq8GO3cQuzZ+HlJdKk3 tMDqvhLble4tPrVkZI4grIg8fL9ERODJJ/8mInelPOkAIASB9YvTQfDxmpbHXR+hlcOu vzFlXwyDikoEtXCuE0IsL04zpYhj0nq3salF4ljJrlxK7dEc+YyQIO9B7s9m44xpQO7F 2jFZCER10hQyD/L8VWgd1EM/OJAXwLAFgigj7xjjmte6FHixpw1FhjGh0ujFnQaeRVHc +bC2FsueJU7T0G0s6CBnxXi/e6dOS5X9uvGVWbhZC+AAa6AVC2gFJTU1h3QmdPYrO+rQ nYMg== X-Gm-Message-State: AOAM532FwoIRK2ujw18ZaOpkSDTmbOLr5wsqBCR1Kju96R+Iptk7wbbi wcMw9ZyID40eHStjZ2wdyn9PSI/pwvog0H3y4Xg= X-Google-Smtp-Source: ABdhPJxDx9yoYUAHz3xm8xGYJw2Whc5LeOLySQ+gde1MxDy14U48GA+4sWoq+PMqRFndt2WFKCbAnaD3jjzKwsz2Zf8= X-Received: by 2002:a25:65c4:: with SMTP id z187mr6045778ybb.113.1631210905529; Thu, 09 Sep 2021 11:08:25 -0700 (PDT) MIME-Version: 1.0 References: <20210908213226.1871016-1-andrii@kernel.org> In-Reply-To: From: Andrii Nakryiko Date: Thu, 9 Sep 2021 11:08:14 -0700 Message-ID: Subject: Re: [PATCH v3 bpf-next] libbpf: add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations To: Daniel Borkmann Cc: Andrii Nakryiko , bpf , Alexei Starovoitov , Quentin Monnet , Kernel Team Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Sep 9, 2021 at 9:37 AM Andrii Nakryiko wrote: > > On Thu, Sep 9, 2021 at 5:58 AM Daniel Borkmann wrote: > > > > On 9/8/21 11:32 PM, Andrii Nakryiko wrote: > > > From: Quentin Monnet > > > > > > Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare > > > the deprecation of two API functions. This macro marks functions as deprecated > > > when libbpf's version reaches the values passed as an argument. > > > > > > As part of this change libbpf_version.h header is added with recorded major > > > (LIBBPF_MAJOR_VERSION) and minor (LIBBPF_MINOR_VERSION) libbpf version macros. > > > They are now part of libbpf public API and can be relied upon by user code. > > > libbpf_version.h is installed system-wide along other libbpf public headers. > > > > > > Due to this new build-time auto-generated header, in-kernel applications > > > relying on libbpf (resolve_btfids, bpftool, bpf_preload) are updated to > > > include libbpf's output directory as part of a list of include search paths. > > > Better fix would be to use libbpf's make_install target to install public API > > > headers, but that clean up is left out as a future improvement. The build > > > changes were tested by building kernel (with KBUILD_OUTPUT and O= specified > > > explicitly), bpftool, libbpf, selftests/bpf, and resolve_btfids builds. No > > > problems were detected. > > > > > > Note that because of the constraints of the C preprocessor we have to write > > > a few lines of macro magic for each version used to prepare deprecation (0.6 > > > for now). > > > > > > Also, use LIBBPF_DEPRECATED_SINCE() to schedule deprecation of > > > btf__get_from_id() and btf__load(), which are replaced by > > > btf__load_from_kernel_by_id() and btf__load_into_kernel(), respectively, > > > starting from future libbpf v0.6. This is part of libbpf 1.0 effort ([0]). > > > > > > [0] Closes: https://github.com/libbpf/libbpf/issues/278 > > > > > > Co-developed-by: Quentin Monnet > > > Signed-off-by: Quentin Monnet > > > Signed-off-by: Andrii Nakryiko > > > --- > > > v2->v3: > > > - adding `sleep 10` revealed two more missing dependencies in resolve_btfids > > > and selftest/bpf's bench, which were fixed (BPF CI); > > > v1->v2: > > > - fix bpf_preload build by adding dependency for iterators/iterators.o on > > > libbpf.a generation (caught by BPF CI); > > > > > > kernel/bpf/preload/Makefile | 7 +++++-- > > > tools/bpf/bpftool/Makefile | 4 ++++ > > > tools/bpf/resolve_btfids/Makefile | 6 ++++-- > > > tools/lib/bpf/Makefile | 24 +++++++++++++++++------- > > > tools/lib/bpf/btf.h | 2 ++ > > > tools/lib/bpf/libbpf_common.h | 19 +++++++++++++++++++ > > > tools/testing/selftests/bpf/Makefile | 4 ++-- > > > 7 files changed, 53 insertions(+), 13 deletions(-) > > > > > > diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile > > > index 1951332dd15f..ac29d4e9a384 100644 > > > --- a/kernel/bpf/preload/Makefile > > > +++ b/kernel/bpf/preload/Makefile > > > @@ -10,12 +10,15 @@ LIBBPF_OUT = $(abspath $(obj)) > > > $(LIBBPF_A): > > > $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a > > > > > > -userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ > > > +userccflags += -I$(LIBBPF_OUT) -I $(srctree)/tools/include/ \ > > > + -I $(srctree)/tools/include/uapi \ > > > -I $(srctree)/tools/lib/ -Wno-unused-result > > > > > > userprogs := bpf_preload_umd > > > > > > -clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ > > > +clean-files := $(userprogs) libbpf_version.h bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ > > > + > > > +$(obj)/iterators/iterators.o: $(LIBBPF_A) > > > > > > bpf_preload_umd-objs := iterators/iterators.o > > > bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz > > > > One small issue I ran into by accident while testing: > > > > [root@linux bpf-next]# make -j8 kernel/bpf/ > > SYNC include/config/auto.conf.cmd > > DESCEND objtool > > CALL scripts/atomic/check-atomics.sh > > CALL scripts/checksyscalls.sh > > CC kernel/bpf/syscall.o > > AR kernel/bpf/preload/built-in.a > > CC [M] kernel/bpf/preload/bpf_preload_kern.o > > CC [U] kernel/bpf/preload/iterators/iterators.o > > In file included from ./tools/lib/bpf/libbpf.h:20, > > from kernel/bpf/preload/iterators/iterators.c:10: > > ./tools/lib/bpf/libbpf_common.h:13:10: fatal error: libbpf_version.h: No such file or directory > > 13 | #include "libbpf_version.h" > > | ^~~~~~~~~~~~~~~~~~ > > compilation terminated. > > make[3]: *** [scripts/Makefile.userprogs:43: kernel/bpf/preload/iterators/iterators.o] Error 1 > > make[3]: *** Waiting for unfinished jobs.... > > make[2]: *** [scripts/Makefile.build:540: kernel/bpf/preload] Error 2 > > make[2]: *** Waiting for unfinished jobs.... > > make[1]: *** [scripts/Makefile.build:540: kernel/bpf] Error 2 > > make: *** [Makefile:1872: kernel] Error 2 > > > > For me it was the case where tools/lib/bpf/ was already built _before_ this patch > > was applied, then I applied it, and just ran make -j8 kernel/bpf/ where the above > > can then be reproduced. I'd assume that as-is, this would affect many folks on update. > > We had a similar issue even before these changes with resolve_btfids > build, because Kbuild doesn't record dependency on libbpf build > properly. I'll see how hard it is to record that in a non-intrusive > way for both resolve_btfids and preload/iterators, because doing `make > resolve_btfids_clean` or, worse, `make clean` isn't great. > Hm... I can't repro this. Both preload/iterators and resolve_btfids have $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) dependency which will trigger libbpf rebuild if any of libbpf source files changes. I added `sleep 1000` and everything under kernel/bpf is blocked on this until libbpf build completes. For full kernel build it also shouldn't happen because we build resolve_btfids first before proceeding to building other files and resolve_btfids should trigger libbpf build. I assume `make clean kernel/bpf` fixed the issue for you in that case? Also, how did you build tools/lib/bpf before running `make -j8 kernel/bpf`? Honestly, hard to tell how this happens without being able to repro this. So far everything seems to be working for me. I've tried with and without the KBUILD_OUTPUT envvar set. I also tried O=. > > > > Thanks, > > Daniel