From patchwork Mon Oct 2 16:57:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13406482 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2733CE784AB for ; Mon, 2 Oct 2023 16:58:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238568AbjJBQ6O (ORCPT ); Mon, 2 Oct 2023 12:58:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238546AbjJBQ6I (ORCPT ); Mon, 2 Oct 2023 12:58:08 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23D00B4; Mon, 2 Oct 2023 09:58:05 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D177DC433CA; Mon, 2 Oct 2023 16:58:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696265884; bh=BdsyPvEj53bRhSrPGLPqhoMZxFh5sEybiAwaA9VVpew=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MoarQNNeg90+ZrJS/8bCWOtdeyip/Ehjh86/RE+EGGzvFDosBwZcGY1z1RQ63OveD SMdtoHLgk61DoaWo1+DjXCqTATkbwX0SsEhgSEop0Ngos/5ZZ3DSfm26vZYJQ6Iqju EJxZisKAzbqHVcj5x2mQ8JsErjOOdCMg4KYsdU5/iD5ER243gBlawhplsUzfDDPEMf kAPfyNyPNRUJ2Dhx9r0HAXeSGtgjlTcj/gPVFyoSlPWvAJbmF6ah3ivJ7MUt+mcjKV eElZNnBThoDIIihUby56Wwn1BWy4wASAaMOEUXf+OoOUtzAUib5VMG++5Wc/IuTEhc T7d7sF6HltmXA== From: Will Deacon To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, Will Deacon , Masahiro Yamada , Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Josh Poimboeuf , John Stultz , linux-kbuild@vger.kernel.org Subject: [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Date: Mon, 2 Oct 2023 17:57:49 +0100 Message-Id: <20231002165750.1661-4-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231002165750.1661-1-will@kernel.org> References: <20231002165750.1661-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Mapping symbols emitted in the readelf output can confuse the 'faddr2line' symbol size calculation, resulting in the erroneous rejection of valid offsets. This is especially prevalent when building an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are prefixed with a 32-bit data value in a '$d.n' section. For example: 447538: ffff800080014b80 548 FUNC GLOBAL DEFAULT 2 do_one_initcall 104: ffff800080014c74 0 NOTYPE LOCAL DEFAULT 2 $x.73 106: ffff800080014d30 0 NOTYPE LOCAL DEFAULT 2 $x.75 111: ffff800080014da4 0 NOTYPE LOCAL DEFAULT 2 $d.78 112: ffff800080014da8 0 NOTYPE LOCAL DEFAULT 2 $x.79 36: ffff800080014de0 200 FUNC LOCAL DEFAULT 2 run_init_process Adding a warning to do_one_initcall() results in: | WARNING: CPU: 0 PID: 1 at init/main.c:1236 do_one_initcall+0xf4/0x260 Which 'faddr2line' refuses to accept: $ ./scripts/faddr2line vmlinux do_one_initcall+0xf4/0x260 skipping do_one_initcall address at 0xffff800080014c74 due to size mismatch (0x260 != 0x224) no match for do_one_initcall+0xf4/0x260 Filter out these entries from readelf using a shell reimplementation of is_mapping_symbol(), so that the size of a symbol is calculated as a delta to the next symbol present in ksymtab. Cc: Josh Poimboeuf Cc: John Stultz Suggested-by: Masahiro Yamada Signed-off-by: Will Deacon Reviewed-by: Nick Desaulniers Reviewed-by: Masahiro Yamada --- scripts/faddr2line | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/scripts/faddr2line b/scripts/faddr2line index 6b8206802157..587415a52b6f 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -179,6 +179,11 @@ __faddr2line() { local cur_sym_elf_size=${fields[2]} local cur_sym_name=${fields[7]:-} + # is_mapping_symbol(cur_sym_name) + if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then + continue + fi + if [[ $cur_sym_addr = $sym_addr ]] && [[ $cur_sym_elf_size = $sym_elf_size ]] && [[ $cur_sym_name = $sym_name ]]; then