From patchwork Thu Sep 14 13:12:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13385200 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 E80C6EE0205 for ; Thu, 14 Sep 2023 13:12:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238939AbjINNMr (ORCPT ); Thu, 14 Sep 2023 09:12:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238893AbjINNMp (ORCPT ); Thu, 14 Sep 2023 09:12:45 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B6C11FF1; Thu, 14 Sep 2023 06:12:39 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96983C43391; Thu, 14 Sep 2023 13:12:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694697159; bh=+CC9mobcRwM0GI3pQyWvu824yuFZxFQDNxuC0AREltc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rh9n+ug2kScz3yTqHUkPgPjvCjkx4S/ESBNOk02rQwKEHvq48uXx7cN5RxyCz961R X/cJo4S2Ko87mLy6MmGcz+LhdL0SkclPFAMnmToQou7Wbl3Xl0EMylAK9neGmURSKz ZhpT/PN/UIxjEzZcCJKoMIiHysCIOwx9hRZtgOWrmGL0adb487gjLHyBnSZBkH9oqY aGezo9Ac7ZH2Pj6hPp4lNGkVicoq0NXHvm5BkQ+l4wPzMsVY2veiTzljEJqTL3ua37 FW+MpvSwOX/D0/Xl3qP8p0H1c85okL4bIHh0Z0RpMZJLVT7LUDkeTcm2VjaO8Pkwbn YZ2Df+iBETITA== 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 v4 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Date: Thu, 14 Sep 2023 14:12:25 +0100 Message-Id: <20230914131225.13415-4-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230914131225.13415-1-will@kernel.org> References: <20230914131225.13415-1-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 --- scripts/faddr2line | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/scripts/faddr2line b/scripts/faddr2line index 6b8206802157..20d9b3d37843 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 [[ ${cur_sym_name} =~ ^((\.L)|(L0)|(\$[adtx](\.|$))) ]]; then + continue + fi + if [[ $cur_sym_addr = $sym_addr ]] && [[ $cur_sym_elf_size = $sym_elf_size ]] && [[ $cur_sym_name = $sym_name ]]; then