From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from v22018116198577468.luckysrv.de (tikei.de [188.68.34.133]) by sourceware.org (Postfix) with ESMTP id 6B7EC3950C61 for ; Tue, 4 May 2021 12:16:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6B7EC3950C61 Received: from smtpclient.apple (unknown [80.149.95.59]) by v22018116198577468.luckysrv.de (Postfix) with ESMTPSA id EFD2B4006C for ; Tue, 4 May 2021 14:16:42 +0200 (CEST) From: Tino Mettler Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.80.0.2.43\)) Subject: Missing .gnu_debugdata section on ARM platform when libdw is used by systemd-coredump Message-Id: <892EDCB7-C2A8-4497-8FF1-986A63EA7F4A@tikei.de> Date: Tue, 4 May 2021 14:15:41 +0200 To: elfutils-devel@sourceware.org X-Mailer: Apple Mail (2.3654.80.0.2.43) X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 May 2021 12:16:44 -0000 Hi, I have a system running on 2 different architectures: AMD64 and ARM. = When a coredump happens, I want systemd-coredump to generate a stack = trace of the crashing application. Systemd depends on elfutils for this = feature. I use binaries with minidebuginfo (the LZMA compressed symbol = table in the .gnu_debugdata section) on both architectures. I get a stack trace on AMD64, but not on ARM. While debugging this, I = saw that find_aux_sym() from dwfl_module_getdwarf.c does not find a = .gnu_debugdata section when iterating through the ELF using = elf_nextscn(). However, it finds a .gnu_debuglink section. I inspected the executable = and verified that it contains a .gnu_debugdata section and it looks = fine. Interestingly, there is no .gnu_debuglink section in the = executable despite elf_nextscn() seems to find one. It looks like libdw does not process the actual executable, but a = modified variant, and the .gnu_debugdata section gets lost at some point = on my ARM device. Can you give me a hint where I need to look at? Both = devices run a different kernel with a different configuration. Could = that be related? I also tried gdb using the coredump file from systemd-coredump and the = same executable, and a stack trace worked as expected. Regards, Tino