From patchwork Tue Jul 25 21:11:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13327032 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 471CAEB64DD for ; Tue, 25 Jul 2023 21:12:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231470AbjGYVMQ (ORCPT ); Tue, 25 Jul 2023 17:12:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231428AbjGYVMP (ORCPT ); Tue, 25 Jul 2023 17:12:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1924419B4; Tue, 25 Jul 2023 14:12:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9F83F61909; Tue, 25 Jul 2023 21:12:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34F86C433CB; Tue, 25 Jul 2023 21:12:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690319533; bh=ARjM/rczxk3PX8PtoECoSFwHH4d2kchH7iqw5zHKaMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Es8WBez048KDHgpfoMTc37khxgywhAUh1Fjp8T+Fcd0GRj+DLQo25GFk11awLdjP4 rRlD28MBQilhGllWoeSs63csGlR2xv7LYvhJcE+ED/e+PF6DAT9ewPVcGZWVrCJpIJ vVVC54hqyEZZXBaUZ1bVhXn+Wdx9ig/Qgl8/tOs2+3WBlksIqY7AfAeCNEt4YDfK/k 1erMGTAbh7j09grtpTOe+e/ExDu0mjGlBe1MjfvA/hXKRMyEJ1QYWAW7gZ7SDF2siI JPyGLNqXQ+Fd6CSNlJmw3H4yzBF0qXlaAu8lVGJ3ft/le4Bi1nHj6sY0CREHxO4GF+ VMWxKh/sfWYQA== 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 v2 2/2] scripts/faddr2line: Constrain readelf output to symbols from System.map Date: Tue, 25 Jul 2023 22:11:57 +0100 Message-Id: <20230725211157.17031-3-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230725211157.17031-1-will@kernel.org> References: <20230725211157.17031-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Some symbols emitted in the readelf output but filtered from System.map 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 entries from readelf using the 'sysmap-ignored-syms.sed' script used to construct System.map, 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 Signed-off-by: Will Deacon --- scripts/faddr2line | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/scripts/faddr2line b/scripts/faddr2line index 62a3fa6f6f59..da734af90036 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -64,6 +64,7 @@ else UTIL_PREFIX=${CROSS_COMPILE:-} fi +IGNORED_SYMS=$(dirname $0)/sysmap-ignored-syms.sed READELF="${UTIL_PREFIX}readelf" ADDR2LINE="${UTIL_PREFIX}addr2line" AWK="awk" @@ -185,7 +186,7 @@ __faddr2line() { found=2 break fi - done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2) + done < <(${READELF} --symbols --wide $objfile | sed -f ${IGNORED_SYMS} -e 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2) if [[ $found = 0 ]]; then warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"