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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 31DA6C35257 for ; Mon, 21 Sep 2020 19:53:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8CF72193E for ; Mon, 21 Sep 2020 19:53:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="XSrOe4XJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727386AbgIUTxz (ORCPT ); Mon, 21 Sep 2020 15:53:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727197AbgIUTxz (ORCPT ); Mon, 21 Sep 2020 15:53:55 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BFF1C061755 for ; Mon, 21 Sep 2020 12:53:55 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id y17so11846584qkf.15 for ; Mon, 21 Sep 2020 12:53:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=NkDZcRY3De1hSvtpPkrbUQZa6hDc7W+Q+JsVyUUmZWE=; b=XSrOe4XJ1v9dbh0GdNneErWkN9R42VSSV9rwWYLstBuo7453koM7EESt3SlO8cibKt srPn5EFgXXhCTQjkwWO5mXUYFm47Y0lCkmnMfuyxPQ2F9zjFDNwJa+kaYm/EPnw6/NJ5 6q1hQpUmOpkXX8IxAIMB7x6PHv3dICVlailSJJ3m1auKeVmC9+vOarJkKqS7Csmc0a4u NwthANxr//Bxsq9+w9raGAoTZz0QqTMF6R/yVsyE9256atiZCFzXKPNwTG4qgY1I3nhM KFyQ6qidbKoiqVC5jR3ID6vnSYMPJwFIrfv+y8QcoxA0+azvs0QytcjvsrWE8+I3VmL9 YjeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=NkDZcRY3De1hSvtpPkrbUQZa6hDc7W+Q+JsVyUUmZWE=; b=NTupewKD6XKXw2M7uzyR/phbrn5Bz/82/RcPKh4R5jL7VatQ3iNvEumqP0lv52aJ86 kCMkb7gF7S++tPlhA//e8WQA/HjfAgI7iw3gImx3s03DAmfDRheq3MQp5IEPB2WE1yOu GFaMYgkuPiM4znjtGE+2i7lsmUmnYy1Olu1iKUX7HJKgc6n3InAF9JxmTr1XQ3TltCvH +uyQK7ODTyNBskVETV5VBccG5JTTgMB1HEIrIxM56z2xb7HfLajMe6WmADQx15skfNZh xu7MCm4wmMdDHP2/EQ+71+W6DT02WmjUbU/OwGHuXhjZCLtWwN84b0zYG2W95k9H8CJB 4siQ== X-Gm-Message-State: AOAM532lOImOUJkAUET2lzrrSMNWbAltQqjtcpiWY4yS7Yt4qCzTk17l JoyeM0GrT1aZurpT1jldKWChPGZ2WIs= X-Google-Smtp-Source: ABdhPJy4Gzdl4oYDxOeqaS3alIPKF5GHgAYIV2HpPP2MLlMDvPhf9SbH62UDcn+yLgLzF6bUmx8v3EslLuE= Sender: "haoluo via sendgmr" X-Received: from haoluo.svl.corp.google.com ([2620:15c:2cd:202:f693:9fff:fef4:e444]) (user=haoluo job=sendgmr) by 2002:a0c:b21b:: with SMTP id x27mr1924162qvd.12.1600718034526; Mon, 21 Sep 2020 12:53:54 -0700 (PDT) Date: Mon, 21 Sep 2020 12:53:09 -0700 In-Reply-To: <20200921195310.3070085-1-haoluo@google.com> Message-Id: <20200921195310.3070085-2-haoluo@google.com> Mime-Version: 1.0 References: <20200921195310.3070085-1-haoluo@google.com> X-Mailer: git-send-email 2.28.0.681.g6f77f65b4e-goog Subject: [PATCH v2 1/2] btf_encoder: Allow disabling BTF var encoding. From: Hao Luo To: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko , Alexei Starovoitov , daniel@iogearbox.net, dwarves@vger.kernel.org, yhs@fb.com, Hao Luo Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org A new feature was introduced in commit f3d9054ba8ff ("btf_encoder: Teach pahole to store percpu variables in vmlinux BTF.") which encodes kernel percpu variables into BTF. Add a flag --skip_encoding_btf_vars to allow users to toggle this feature off, so that the rollout of pahole v1.18 can be protected by potential bugs in this feature. Signed-off-by: Hao Luo --- btf_encoder.c | 5 ++++- btf_encoder.h | 3 ++- pahole.c | 11 ++++++++++- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/btf_encoder.c b/btf_encoder.c index 982f59d..d26c0b6 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -237,7 +237,8 @@ static struct variable *hashaddr__find_variable(const struct hlist_head hashtabl return NULL; } -int cu__encode_btf(struct cu *cu, int verbose, bool force) +int cu__encode_btf(struct cu *cu, int verbose, bool force, + bool skip_encoding_vars) { bool add_index_type = false; uint32_t type_id_off; @@ -314,6 +315,8 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force) } } + if (skip_encoding_vars) + goto out; if (btfe->percpu_shndx == 0 || !btfe->symtab) goto out; diff --git a/btf_encoder.h b/btf_encoder.h index bca2348..46fb231 100644 --- a/btf_encoder.h +++ b/btf_encoder.h @@ -13,6 +13,7 @@ struct cu; int btf_encoder__encode(); -int cu__encode_btf(struct cu *cu, int verbose, bool force); +int cu__encode_btf(struct cu *cu, int verbose, bool force, + bool skip_encoding_vars); #endif /* _BTF_ENCODER_H_ */ diff --git a/pahole.c b/pahole.c index e1cde61..4cc8d9f 100644 --- a/pahole.c +++ b/pahole.c @@ -26,6 +26,7 @@ static bool btf_encode; static bool ctf_encode; static bool first_obj_only; +static bool skip_encoding_btf_vars; static uint8_t class__include_anonymous; static uint8_t class__include_nested_anonymous; @@ -809,6 +810,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; #define ARGP_header_type 314 #define ARGP_size_bytes 315 #define ARGP_range 316 +#define ARGP_skip_encoding_btf_vars 317 static const struct argp_option pahole__options[] = { { @@ -1087,6 +1089,11 @@ static const struct argp_option pahole__options[] = { .key = 'J', .doc = "Encode as BTF", }, + { + .name = "skip_encoding_btf_vars", + .key = ARGP_skip_encoding_btf_vars, + .doc = "Do not encode VARs in BTF." + }, { .name = "force", .key = 'j', @@ -1207,6 +1214,8 @@ static error_t pahole__options_parser(int key, char *arg, conf.range = arg; break; case ARGP_header_type: conf.header_type = arg; break; + case ARGP_skip_encoding_btf_vars: + skip_encoding_btf_vars = true; break; default: return ARGP_ERR_UNKNOWN; } @@ -2352,7 +2361,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu, goto filter_it; if (btf_encode) { - cu__encode_btf(cu, global_verbose, force); + cu__encode_btf(cu, global_verbose, force, skip_encoding_btf_vars); return LSK__KEEPIT; } -- 2.28.0.681.g6f77f65b4e-goog