From patchwork Mon Apr 17 09:17:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom de Vries X-Patchwork-Id: 67806 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 452313857703 for ; Mon, 17 Apr 2023 09:18:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 452313857703 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1681723085; bh=/6n++gh+yjnb6jg9E/aXsDttrzvHAhf3G36auKsulCk=; h=To:Cc:Subject:Date:List-Id:List-Unsubscribe:List-Archive: List-Post:List-Help:List-Subscribe:From:Reply-To:From; b=hf48WFm4xk4RJ9+IF8KXivQ0+yAM4jTCNCOA2bzjO3WQbo0wpPsKbGep4Ev47g7Jp nv2ZGvbyvMNd29emjkgW4JQHO8wrXi2v4+29xrfZNIwJ+qQge/Da/6KbNkEDZ46aKf VmL4flrdK4k+SyxC44Zu6sXf48EsVHsuPLye9NeY= X-Original-To: gdb-patches@sourceware.org Delivered-To: gdb-patches@sourceware.org Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by sourceware.org (Postfix) with ESMTPS id DA74A3857722 for ; Mon, 17 Apr 2023 09:17:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org DA74A3857722 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 1D1881F38D; Mon, 17 Apr 2023 09:17:31 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 05BC413319; Mon, 17 Apr 2023 09:17:30 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id s7uFO6oOPWQOXgAAMHmgww (envelope-from ); Mon, 17 Apr 2023 09:17:30 +0000 To: gdb-patches@sourceware.org Cc: Tom Tromey Subject: [PATCH] [gdb/symtab] Handle empty file name in .debug_line section Date: Mon, 17 Apr 2023 11:17:28 +0200 Message-Id: <20230417091728.26004-1-tdevries@suse.de> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 X-Spam-Status: No, score=-12.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Tom de Vries via Gdb-patches From: Tom de Vries Reply-To: Tom de Vries Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" With DWARF 5, it's possible to produce an empty file name in the File Name Table of the .debug_line section: ... The File Name Table (offset 0x112, lines 1, columns 2): Entry Dir Name 0 1 (indirect line string, offset: 0x2d): ... Currently, when gdb reads an exec containing such debug info, it segfaults: ... Thread 1 "gdb" received signal SIGSEGV, Segmentation fault. 0x000000000072cd38 in dwarf2_start_subfile (cu=0x2badc50, fe=..., lh=...) at \ gdb/dwarf2/read.c:18716 18716 if (!IS_ABSOLUTE_PATH (filename) && dirname != NULL) ... because read_direct_string transforms "" into a nullptr, and we end up dereferencing the nullptr. Note that the behaviour of read_direct_string has been present since repo creation. Fix this in read_formatted_entries, by transforming nullptr filenames in to "" filenames. Tested on x86_64-linux. PR symtab/30357 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30357 Reviewed-By: Tom Tromey --- gdb/dwarf2/line-header.c | 4 ++ .../gdb.dwarf2/dw2-empty-file-name.exp | 66 +++++++++++++++++++ 2 files changed, 70 insertions(+) create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-empty-file-name.exp base-commit: 55003828f4d81a3d857ccfdfe4841704004a6468 diff --git a/gdb/dwarf2/line-header.c b/gdb/dwarf2/line-header.c index 9d74c8fe75b..d072a91bac9 100644 --- a/gdb/dwarf2/line-header.c +++ b/gdb/dwarf2/line-header.c @@ -215,6 +215,10 @@ read_formatted_entries (dwarf2_per_objfile *per_objfile, bfd *abfd, break; } + /* Normalize nullptr string. */ + if (string.has_value () && *string == nullptr) + string.emplace (""); + switch (content_type) { case DW_LNCT_path: diff --git a/gdb/testsuite/gdb.dwarf2/dw2-empty-file-name.exp b/gdb/testsuite/gdb.dwarf2/dw2-empty-file-name.exp new file mode 100644 index 00000000000..6030e4a0579 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/dw2-empty-file-name.exp @@ -0,0 +1,66 @@ +# Copyright 2023 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Check that an empty file name in the .debug_line section doesn't cause +# problems. + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +require dwarf2_support + +# The .c files use __attribute__. +require is_c_compiler_gcc + +standard_testfile main.c -dw.S + +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + declare_labels Llines + global srcdir subdir srcfile + + cu { version 5 } { + compile_unit { + {language @DW_LANG_C} + {name $srcfile} + {stmt_list $Llines DW_FORM_sec_offset} + } { + subprogram { + {external 1 flag} + {MACRO_AT_func {main}} + } + } + } + + lines {version 5} Llines { + include_dir "${srcdir}/${subdir}" + file_name "" 1 + } +} + +if { [build_executable "failed to prepare" ${testfile} \ + [list $srcfile $asm_file] {nodebug}] } { + return -1 +} + +clean_restart + +# If there's an ERROR during gdb_load, the assert will produce an UNRESOLVED +# rather than a FAIL. +gdb_assert { [gdb_load $binfile] == 0 } + +# But this will produce an actual FAIL, which is more visible than +# ERROR/UNRESOLVED. +gdb_assert { [info exists gdb_spawn_id] }