From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id C0D7D3858D28 for ; Fri, 4 Feb 2022 16:09:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C0D7D3858D28 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-399-ft8NGXCBOMOVI9Wnd0GknQ-1; Fri, 04 Feb 2022 11:09:14 -0500 X-MC-Unique: ft8NGXCBOMOVI9Wnd0GknQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AD479100E320; Fri, 4 Feb 2022 16:09:13 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D417479A2B; Fri, 4 Feb 2022 16:09:12 +0000 (UTC) From: Florian Weimer To: Jacob Kroon Cc: Jacob Kroon via Gdb Subject: Re: Debugging ld.so in gdb References: <29e0ef71-4706-9b0f-2a68-e12c54120d8e@gmail.com> <8735kypwcd.fsf@oldenburg.str.redhat.com> <87y22qognw.fsf@oldenburg.str.redhat.com> Date: Fri, 04 Feb 2022 17:09:10 +0100 In-Reply-To: (Jacob Kroon's message of "Fri, 4 Feb 2022 15:27:15 +0100") Message-ID: <87h79eobq1.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-6.2 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Feb 2022 16:09:20 -0000 * Jacob Kroon: > On 2/4/22 15:22, Florian Weimer wrote: >> * Jacob Kroon: >>=20 >>> This is what I get, following the instructions above: >>> >>>> 171966=09 0x00007ffff7fd85a0 :=09mov 0x0(%r13),= %rax >>>> 171967=09 0x00007ffff7fd85a4 :=09lea -0x8(%rax)= ,%rdx >>>> 171968=09 0x00007ffff7fd85a8 :=09mov %rdx,0x0(%= r13) >>>> 171969=09 0x00007ffff7fd85ac :=09mov %rbp,-0x8(= %rax) >>>> 171970=09 0x00007ffff7fd85b0 :=09add $0x8,%rsp >>>> 171971=09 0x00007ffff7fd85b4 :=09pop %rbx >>>> 171972=09 0x00007ffff7fd85b5 :=09pop %rbp >>>> 171973=09 0x00007ffff7fd85b6 :=09pop %r12 >>>> 171974=09 0x00007ffff7fd85b8 :=09pop %r13 >>>> 171975=09 0x00007ffff7fd85ba :=09ret =20 >>> >>> Does that make sense ? Any other information I can provide. This is wit= h >>> glibc-2.34-24.fc35.x86_64, Fedora 35. >>=20 >> This doesn't really make sense. There's probably some GDB option to get >> a longer trace. >>=20 >> If it is crashing at the RET, it means that either code has been mapped >> over, or the stack has been corrupted. At the crash site, what does >>=20 >> print *(void**)$rsp >>=20 >> print? >>=20 > > $2 =3D (void *) 0x7ffff7d31b70 > >> disassemble *(void**)$rsp >>=20 >> could also be interesting. >>=20 > > "No function contains specified address" > > Let me see if I can find some gdb option to get a longer trace. Looks like the code at that address has been unmapped (or the link map is at least gone from a GDB perspective). Maybe you can see what was at the address before using =E2=80=9Cinfo files=E2=80=9D? Thanks, Florian