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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id AA2C83894C24 for ; Fri, 7 May 2021 20:44:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org AA2C83894C24 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-491-glBmuqYcOwqaKWu1dcKCIw-1; Fri, 07 May 2021 16:44:08 -0400 X-MC-Unique: glBmuqYcOwqaKWu1dcKCIw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 766B480575A; Fri, 7 May 2021 20:43:57 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-137.ams2.redhat.com [10.36.112.137]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3A4555D6AB; Fri, 7 May 2021 20:43:55 +0000 (UTC) From: Florian Weimer To: Luis Machado via Libc-alpha Cc: "gdb@sourceware.org" , Luis Machado , doko@debian.org Subject: Re: GDB shared library tracking with stap probes x _dl_debug_state References: Date: Fri, 07 May 2021 22:44:16 +0200 In-Reply-To: (Luis Machado via Libc-alpha's message of "Fri, 7 May 2021 16:42:03 -0300") Message-ID: <878s4qb7fj.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 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, 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: 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, 07 May 2021 20:44:14 -0000 * Luis Machado via Libc-alpha: > That's all fine, but there is one small detail that doesn't work for > armhf, and that is discovering if we're dealing with a PC that is arm > mode or thumb mode. Is it possible to recognize Arm mode vs thumb mode based on the NOP encoding at the probe address? > 2 - Not stripping ld.so/glibc. I can't determine the impact of this > choice, but distros strip binaries for a reason. Having to carry all > symbols for a particular library may not be desirable. We are switching Fedora to not strip ld.so, primarily for introspection purposes in Systemtap. (In Fedora, we've preserved the symbol table for ages, to make valgrind work.) Thanks, Florian