From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id 6r1JLOcYpGrAVwAAWB0awg (envelope-from ) for ; Fri, 11 Sep 2026 11:06:15 -0400 Authentication-Results: simark.ca; dkim=pass (1024-bit key; unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=t9wUZ7kJ; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=0hde3sY9; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=0r7tyReZ; dkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=IbkjSvEq; dkim-atps=neutral Received: by simark.ca (Postfix, from userid 112) id A2D211E09E; Fri, 11 Sep 2026 11:06:15 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-25) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=ARC_SIGNED,ARC_VALID,BAYES_00, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_VALIDITY_CERTIFIED_BLOCKED, RCVD_IN_VALIDITY_RPBL_BLOCKED,RCVD_IN_VALIDITY_SAFE_BLOCKED autolearn=ham autolearn_force=no version=4.0.1 Received: from vm01.sourceware.org (vm01.sourceware.org [38.145.34.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 9CF0A1E091 for ; Fri, 11 Sep 2026 11:06:14 -0400 (EDT) Received: from vm01.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 4C71D48F664F for ; Fri, 11 Sep 2026 15:06:13 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4C71D48F664F Authentication-Results: sourceware.org; dkim=pass (1024-bit key, unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=t9wUZ7kJ; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=0hde3sY9; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=0r7tyReZ; dkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=IbkjSvEq Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2a07:de40:b251:101:10:150:64:2]) by sourceware.org (Postfix) with ESMTPS id 94A314BBCDA6 for ; Fri, 11 Sep 2026 15:05:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 94A314BBCDA6 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 94A314BBCDA6 Authentication-Results: sourceware.org; arc=none smtp.remote-ip=2a07:de40:b251:101:10:150:64:2 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1789139146; cv=none; b=Bv8uJ7HvavDn+maJzgc6Eo4y3x0cd4faCjin4A2ojH8qZd2ZZkEyqJvlLLMtCLADXWv6acoZosrJ7SbYXK555NqJftRIXNEwbQdQybPDyDmDjPYq3qlU1oGUQUipYFf4fiP7RrZuyt1QNuLiSC79s4ouL4YWweNot2IbZl/8nHA= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1789139146; c=relaxed/simple; bh=PtjakHytdvw+YmxeFGPBZqRJx5eG5ngU0jrILk7N4Po=; h=DKIM-Signature:DKIM-Signature:DKIM-Signature:DKIM-Signature:From: To:Subject:Date:Message-ID:MIME-Version; b=q09nLzVgD+OWieAuv64rM5w7ZfugB5PHj985BeTqV2WlDXVr1H22zslIqUW80PzlggBrtcfGOGuPbsmL1jhSa3+9tSRxSEYG6ymdr48Csg/2NKj/8Oc4okhkDzLa+xeFhk3lAufj7oE0zoKepJ3Vxhj40sZqN2fjGIOFRt9Xkt0= ARC-Authentication-Results: i=1; sourceware.org; dkim=pass (1024-bit key, unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=t9wUZ7kJ; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=0hde3sY9; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=0r7tyReZ; dkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=IbkjSvEq DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 94A314BBCDA6 Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 50C451FEF2 for ; Fri, 11 Sep 2026 15:05:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1789139141; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=lHBGzz7fOCFOfjuWTV0KPmpHpng4lQdVmJTQGZsocUI=; b=t9wUZ7kJ8q+jip5DWV1ySKs7HKpr/lPTIpJQ1fgfHchvtKuDzXxQcXQCDTqPGvSH6WOxAW 6aDjmWl6U0Pg4Y8jOo9wYGQJzR465aj+ChZvecvopHkJszSE9yg/GlsRVbixWt9PqvZpoi cFLgOsg+F9wHxUno19qnM3q5DWJSv3c= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1789139141; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=lHBGzz7fOCFOfjuWTV0KPmpHpng4lQdVmJTQGZsocUI=; b=0hde3sY9rxCrg5WzglT7CrLOoN4EDnm62lal9tWKrIVTyYbel3JpTATDWqAp81QX3sPcwE 1GkN6QvzYcaBAcAw== Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=0r7tyReZ; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=IbkjSvEq DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1789139137; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=lHBGzz7fOCFOfjuWTV0KPmpHpng4lQdVmJTQGZsocUI=; b=0r7tyReZrPQdYlNfutWI2xnsaRYKxtSYgyTxViQCxXd7iH6l/sBr3z1WiOcw3Yp6Ytk8et rjdSqMMVKXyG5Eg+A3Fe3rpLA2cKlcpDyQgaM40LYcDC96oLxrQPFzwuVUlZy0fYt7Ithp mrXeufvoYdTYp6ll2tOMcWHSdj17bkU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1789139137; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=lHBGzz7fOCFOfjuWTV0KPmpHpng4lQdVmJTQGZsocUI=; b=IbkjSvEq7u4/XE3Rb6IlVeQJJIBN4J0d9LDVVmbGJ2XjLWThAGWvLpdz5Ks7/n6A2LZuL7 5i5AksOIbcTZpMCg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 1C71913770 for ; Fri, 11 Sep 2026 15:05:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id dNtdAcEYpGrUHgAAD6G6ig (envelope-from ) for ; Fri, 11 Sep 2026 15:05:37 +0000 From: Tom de Vries To: gdb-patches@sourceware.org Subject: [PATCH] [gdb] Detect corrupt link map with zero l_ld and l_addr Date: Fri, 11 Sep 2026 17:05:36 +0200 Message-ID: <20260911150536.2712756-1-tdevries@suse.de> X-Mailer: git-send-email 2.51.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 50C451FEF2 X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; MIME_TRACE(0.00)[0:+]; FROM_HAS_DN(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[gdb-patches@sourceware.org]; FROM_EQ_ENVFROM(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[sourceware.org:url,almalinux.org:url,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,ld.so:url,suse.de:dkim,suse.de:mid]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCVD_TLS_ALL(0.00)[]; TO_DN_NONE(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DKIM_TRACE(0.00)[suse.de:+] X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces~public-inbox=simark.ca@sourceware.org On ppc64le-linux (AlmaLinux 9.8), I run into: ... FAIL: gdb.mi/mi-dlmopen.exp: still-in-use fields were all correct ... While investigating this, I stumbled on this warning emitted during the calculation of allow_dlmopen_tests: ... (gdb) run ^M Starting program: allow_dlmopen_tests.x ^M [Thread debugging using libthread_db enabled]^M Using host libthread_db library "/lib64/libthread_db.so.1".^M warning: .dynamic section for "/lib64/ld64.so.2" is not at the expected \ address (wrong library or version mismatch?)^M dlmopen debug supported.^M ... The warning is mentioned in this glibc commit 88361b408b: ... elf: Copy l_addr/l_ld when adding ld.so to a new namespace When add ld.so to a new namespace, we don't actually load ld.so. We create a new link map and refers the real one for almost everything. Copy l_addr and l_ld from the real ld.so link map to avoid GDB warning: warning: .dynamic section for ".../elf/ld-linux-x86-64.so.2" is not at \ the expected address (wrong library or version mismatch?) when handling shared library loaded by dlmopen. ... So, AFAICT the setup is: - the glibc package is based on v2.34 - it contains a backport of commit a93d9e03a3 ("Extend struct r_debug to support multiple namespaces [BZ #15971]") - it doesn't contain a backport of commit 88361b408b ("elf: Copy l_addr/l_ld when adding ld.so to a new namespace") [1] - both commits are part of v2.35 What happens is: - when probing for l_addr and l_ld in svr4_solib_ops::read_lm_info, both get the value 0 - in svr4_solib_ops::lm_addr_check, the 0 value propagates to l_dynaddr, and "l_addr = l_dynaddr - dynaddr" then underflows, and things go downhill from there, resulting in the warning and eventually the FAIL. Fix this by detecting the situation in svr4_solib_ops::read_so_list, and bailing out with a warning. Add detection of this and other "corruption" warnings in allow_dlmopen_tests to make sure the related test-cases are skipped. In more detail, before this patch we have: ... $ gdb -q -batch outputs/gdb.base/dlmopen/dlmopen -ex start -ex next \ -ex "pipe info shared | ld64" ... warning: .dynamic section for "/lib64/ld64.so.2" is not at the expected \ address (wrong library or version mismatch?) ... 0x00007ffff7f80000 0x00007ffff8000000 0 Yes /lib64/ld64.so.2 0x0000000000000160 0xffffffffffff0000 1 Yes /lib64/ld64.so.2 ... and after: ... warning: Corrupted shared library entry: zero l_addr and l_ld warning: Corrupted shared library entry: zero l_addr and l_ld ... 0x00007ffff7f80000 0x00007ffff8000000 0 Yes /lib64/ld64.so.2 ... Alternatively, we could prevent the underflow in svr4_solib_ops::lm_addr_check: ... bool l_addr_updated = false; if (l_dynaddr >= dynaddr) { l_addr = l_dynaddr - dynaddr; l_addr_updated = true; } if (l_addr_updated && (l_addr & (minpagesize - 1)) == 0 && (l_addr & align) == ((l_dynaddr - dynaddr) & align)) ... but we'd still get an incorrect range: ... warning: .dynamic section for "/lib64/ld64.so.2" is not at the expected \ address (wrong library or version mismatch?) ... 0x00007ffff7f80000 0x00007ffff8000000 0 Yes /lib64/ld64.so.2 0x0000000000060000 0x0000000000080000 1 Yes /lib64/ld64.so.2 ... FTR, in an earlier attempt I proposed to deal with the FAIL using an xfail [1]. And in an another attempt I proposed to deal with it by replicating the glibc fix in gdb [3]. Tested on ppc64le-linux and x86_64-linux. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33662 [1] https://bugs.almalinux.org/view.php?id=667 [2] https://sourceware.org/pipermail/gdb-patches/2026-July/229073.html [3] https://sourceware.org/pipermail/gdb-patches/2026-August/229549.html --- gdb/solib-svr4.c | 23 +++++++++++++++++++++++ gdb/testsuite/lib/gdb.exp | 3 +++ 2 files changed, 26 insertions(+) diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index c4af1b11a4d..50a94170cb3 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -1333,6 +1333,29 @@ svr4_solib_ops::read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm, if (*name == '\0' || match_main (name.get ())) continue; + gdb_byte dummy; + if (li->l_addr_inferior == 0 && li->l_ld == 0 + && target_read_memory (0, &dummy, 1) != 0) + { + /* We have l_addr_inferior == 0 and l_ld == 0 (corresponding to link + map entries l_addr and l_ld). This can happen with a glibc that: + - has commit a93d9e03a3 ("Extend struct r_debug to support + multiple namespaces [BZ #15971]"), but + - misses commit 88361b408b ("elf: Copy l_addr/l_ld when adding + ld.so to a new namespace"). + This seems to be the case at least for the alma linux 9.8 BaseOS + version, which uses glibc v2.34 and backports only the first + commit ( https://bugs.almalinux.org/view.php?id=667 ). + Detect this here and bail out. Otherwise, we'll present + the user with incorrect info for "info shared". + + The target_read_memory is there to detect the improbable + situation that address 0 is both mapped, and the address of the + dynamic section. */ + warning (_("Corrupted shared library entry: zero l_addr and l_ld")); + return 0; + } + sos.emplace_back (name.get (), std::move (li)); } diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp index 1ebdaf6ba10..06ebf65e921 100644 --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -3201,6 +3201,9 @@ gdb_caching_proc allow_dlmopen_tests {} { return 0 } gdb_expect { + -re "warning: Corrupted.*$gdb_prompt $" { + set allow_dlmopen_tests 0 + } -re "$inferior_exited_re normally.*${gdb_prompt} $" { set allow_dlmopen_tests 1 } base-commit: 0855b93cfb911a4feab76a31bb1914982b3e6979 -- 2.51.0