From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B7B361A0AEA for ; Tue, 30 Apr 2024 20:42:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714509738; cv=none; b=K499TBZIKwYICsi+lOoSQjW2eXF9LXRjaGgYXqpHqvWppBx29zYdqTF5hWNSzmldFB97svfbQvIFzMQWVMfCTeEFzyzKCpWfn3e+ha3KlkjQeMOkjQJzXrVMq/0mmYxcL51Tv+iZcCuTFJfi6NZ2ugaxfH0/Ke6Ff96o18WwoEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714509738; c=relaxed/simple; bh=C7Irxux/j6sospZeqmB6rrCIosUYGm57yn0RRhl3PAk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uUve76j4V1mFMmq8N95Mcj9UxWWg7MWInoJfLVE2MVJvFfrmILV1HAoncnaHGVUtQ/YWeNzzldyPJ2/Xtcg4EXbZzo1Zy+/qgxRjluu34Hyc+XDlpOXlCnp58CP5doDIbbOsCi8jP8H/+/xde9OMMzfAv+2VfigdJvTDcWK0sbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WdCjtm6k; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WdCjtm6k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F705C2BBFC; Tue, 30 Apr 2024 20:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714509738; bh=C7Irxux/j6sospZeqmB6rrCIosUYGm57yn0RRhl3PAk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WdCjtm6kkji3U2fnZX/g5OXJTL9K2Gla8D809L6Tcty9K6yA9ctzamzvvdevjQ/UB Kov1jrqOn+OgwjnL45Oqz/PlrWp9bmjqzkwUfe2n3LONcYdEwoTvugrcC43Dll2P4r qsY1VRf/qF2oO6GYo2bD8q3yqBBimy5o1nbsLppawIJgB1B182g5G59xbl+5OuVXXN KCtkqKHKRtcIKv0/sWxWPOsDOmYN/m22qYdJm1FPBonTNGGWVb8pDGO7j6UraaJhAp R6SUamis4A4u5AsQyC3KX2Lh/4fijuO5ScRIefcC4RsgO4haTfgDELlBfy3Jpnx3Q3 DsaYLMY+1h51w== Date: Tue, 30 Apr 2024 17:42:14 -0300 From: Arnaldo Carvalho de Melo To: Daniel Xu Cc: jolsa@kernel.org, quentin@isovalent.com, alan.maguire@oracle.com, eddyz87@gmail.com, andrii.nakryiko@gmail.com, ast@kernel.org, daniel@iogearbox.net, bpf@vger.kernel.org Subject: Re: [PATCH dwarves v9 3/3] pahole: Inject kfunc decl tags into BTF Message-ID: References: <26ec519a00aa47f25bc6b4c7e4e15e5191ba4d45.1714430735.git.dxu@dxuuu.xyz> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <26ec519a00aa47f25bc6b4c7e4e15e5191ba4d45.1714430735.git.dxu@dxuuu.xyz> On Mon, Apr 29, 2024 at 04:46:00PM -0600, Daniel Xu wrote: > This commit teaches pahole to parse symbols in .BTF_ids section in > vmlinux and discover exported kfuncs. Pahole then takes the list of > kfuncs and injects a BTF_KIND_DECL_TAG for each kfunc. > > Example of encoding: > > $ bpftool btf dump file .tmp_vmlinux.btf | rg "DECL_TAG 'bpf_kfunc'" | wc -l > 121 > > $ bpftool btf dump file .tmp_vmlinux.btf | rg 56337 > [56337] FUNC 'bpf_ct_change_timeout' type_id=56336 linkage=static > [127861] DECL_TAG 'bpf_kfunc' type_id=56337 component_idx=-1 > > This enables downstream users and tools to dynamically discover which > kfuncs are available on a system by parsing vmlinux or module BTF, both > available in /sys/kernel/btf. > > This feature is enabled with --btf_features=decl_tag,decl_tag_kfuncs. I'm trying this but: ⬢[acme@toolbox pahole]$ time pahole -j --btf_features=decl_tag,decl_tag_kfuncs --btf_encode_detached=vmlinux.btf.decl_tag,decl_tag_kfuncs vmlinux btf_encoder__tag_kfuncs(cgroup_rstat_updated): found=0 btf_encoder__tag_kfuncs(cgroup_rstat_flush): found=0 btf_encoder__tag_kfuncs(security_file_permission): found=0 btf_encoder__tag_kfuncs(security_inode_getattr): found=0 btf_encoder__tag_kfuncs(security_file_open): found=0 btf_encoder__tag_kfuncs(security_path_truncate): found=0 btf_encoder__tag_kfuncs(vfs_truncate): found=0 btf_encoder__tag_kfuncs(vfs_fallocate): found=0 btf_encoder__tag_kfuncs(dentry_open): found=0 btf_encoder__tag_kfuncs(vfs_getattr): found=0 btf_encoder__tag_kfuncs(filp_close): found=0 btf_encoder__tag_kfuncs(bpf_lookup_user_key): found=0 btf_encoder__tag_kfuncs(bpf_lookup_system_key): found=0 btf_encoder__tag_kfuncs(bpf_key_put): found=0 btf_encoder__tag_kfuncs(bpf_verify_pkcs7_signature): found=0 btf_encoder__tag_kfuncs(bpf_obj_new_impl): found=0 With: ⬢[acme@toolbox pahole]$ git diff -U16 diff --git a/btf_encoder.c b/btf_encoder.c index c2df2bc7a374447b..27a16d6564381b60 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -1689,32 +1689,35 @@ static int btf_encoder__tag_kfuncs(struct btf_encoder *encoder) func = get_func_name(name); if (!func) continue; /* Check if function belongs to a kfunc set */ ranges = gobuffer__entries(&btf_kfunc_ranges); ranges_cnt = gobuffer__nr_entries(&btf_kfunc_ranges); found = false; for (j = 0; j < ranges_cnt; j++) { size_t addr = sym.st_value; if (ranges[j].start <= addr && addr < ranges[j].end) { found = true; break; } } + + printf("%s(%s): found=%d\n", __func__, func, found); + if (!found) { free(func); continue; } err = btf_encoder__tag_kfunc(encoder, &btf_funcs, func); if (err) { fprintf(stderr, "%s: failed to tag kfunc '%s'\n", __func__, func); free(func); goto out; } free(func); } err = 0; out: -------------- The vmlinux I'm testing on has the kfuncs, etc, as we can see with: ⬢[acme@toolbox pahole]$ readelf -sW vmlinux | grep __BTF_ID__func__ | wc -l 517 ⬢[acme@toolbox pahole]$ readelf -sW vmlinux | grep __BTF_ID__func__ | tail 97887: ffffffff83266bfc 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__cubictcp_cong_avoid__805493 97888: ffffffff83266c04 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__cubictcp_state__806494 97889: ffffffff83266c0c 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__cubictcp_cwnd_event__807495 97890: ffffffff83266c14 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__cubictcp_acked__808496 98068: ffffffff83266c24 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__tcp_reno_ssthresh__773199 98069: ffffffff83266c2c 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__tcp_reno_cong_avoid__774200 98070: ffffffff83266c34 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__tcp_reno_undo_cwnd__775201 98071: ffffffff83266c3c 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__tcp_slow_start__776202 98072: ffffffff83266c44 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__tcp_cong_avoid_ai__777203 101522: ffffffff83266c5c 4 OBJECT LOCAL DEFAULT 15 __BTF_ID__func__update_socket_protocol__80024 ⬢[acme@toolbox pahole]$ So that btf_encoder__tag_kfuncs() isn't finding any? $ pahole -j --btf_features=decl_tag,decl_tag_kfuncs --btf_encode_detached=vmlinux.btf.decl_tag,decl_tag_kfuncs vmlinux btf_encoder__tag_kfuncs(vmlinux) Yeah, getting the source filename, the right one. Then is_sym_kfunc_set() never returns true... But: ⬢[acme@toolbox pahole]$ time pahole -j --btf_features=decl_tag,decl_tag_kfuncs --btf_encode_detached=vmlinux.btf.decl_tag,decl_tag_kfuncs vmlinux is_sym_kfunc_set(__BTF_ID__set8__bpf_rstat_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__key_sig_kfunc_set, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__generic_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__common_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_map_iter_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__cpumask_kfunc_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_fmodret_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_syscall_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_skb, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_xdp, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_sock_addr, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_sk_iter_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__xdp_metadata_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_test_modify_return_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__test_sk_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__tcp_cubic_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_tcp_ca_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) is_sym_kfunc_set(__BTF_ID__set8__bpf_mptcp_fmodret_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__) real 0m5.586s user 0m29.707s sys 0m2.160s ⬢[acme@toolbox pahole]$ And then: ⬢[acme@toolbox pahole]$ time pahole -j --btf_features=decl_tag,decl_tag_kfuncs --btf_encode_detached=vmlinux.btf.decl_tag,decl_tag_kfuncs vmlinux is_sym_kfunc_set(__BTF_ID__set8__bpf_rstat_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__key_sig_kfunc_set, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__generic_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__common_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_map_iter_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__cpumask_kfunc_btf_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_fmodret_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__hid_bpf_syscall_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_skb, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_xdp, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_kfunc_check_set_sock_addr, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_sk_iter_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__xdp_metadata_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_test_modify_return_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__test_sk_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__tcp_cubic_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_tcp_ca_check_kfunc_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) is_sym_kfunc_set(__BTF_ID__set8__bpf_mptcp_fmodret_ids, BTF_ID_SET8_PFX=__BTF_ID__set8__, set->flags= 0, BTF_SET8_KFUNCS=1, ret=0) real 0m5.597s user 0m29.620s sys 0m2.138s ⬢[acme@toolbox pahole]$ Run out of time, I probably am using an old vmlinux, will try later with one generated from a current kernel, or maybe you guys point to my st00pidity saying what I am missing 8-) - Arnaldo