From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id 0i11IGa2eWCbFgAAWB0awg (envelope-from ) for ; Fri, 16 Apr 2021 12:08:06 -0400 Received: by simark.ca (Postfix, from userid 112) id 75AA31F104; Fri, 16 Apr 2021 12:08:06 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 015881E813 for ; Fri, 16 Apr 2021 12:08:05 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 75FC1398B17A; Fri, 16 Apr 2021 16:08:04 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 75FC1398B17A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1618589284; bh=+jqoFBUHTDnv9PGPcTDpI8wyRnNwnojGcuaw2kodCSI=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=JiKLd8VCuNWvvxP8CVbeLVFv7ZJ7QNQ3zFmikdV6zGqek+TgenWy8W11OVIEqO5Cx MVM4Nk40Rc19chRhQc+VaSbP3TKkrJ7O6UNKeEqAZMO8bK+ssTCdVREfou0pW7gxHa ucfSDGJmYsNwOh3eZvfR/Fd0XZYaJN2GlPh50OCk= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 4BFC53893642; Fri, 16 Apr 2021 16:08:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 4BFC53893642 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 13GG7sLh009148 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 16 Apr 2021 12:07:59 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 13GG7sLh009148 Received: from [10.0.0.11] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id 3B6A61E813; Fri, 16 Apr 2021 12:07:54 -0400 (EDT) Subject: Re: [PATCH glibc] nptl_db: different libpthread/ld.so load orders (bug 27744) To: Florian Weimer , libc-alpha@sourceware.org, gdb-patches@sourceware.org References: <87sg3qnrz3.fsf@oldenburg.str.redhat.com> Message-ID: <73b32cc6-e201-8bac-e442-e3dddcc01e0d@polymtl.ca> Date: Fri, 16 Apr 2021 12:07:53 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <87sg3qnrz3.fsf@oldenburg.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Fri, 16 Apr 2021 16:07:54 +0000 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: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Cc: Pedro Alves , Emil Velikov Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" On 2021-04-16 11:56 a.m., Florian Weimer wrote: > libthread_db is loaded once GDB encounters libpthread, and at this > point, ld.so may not have been loaded yet. Hi Florian, Can this state (libpthread loaded, ld.so not loaded) really happen during the normal lifetime of a process? My understanding is that this state happens when attaching only because GDB reads the shared libraries from the process in an undefined order, so libpthread may be discovered before ld.so. So we present to libthread_db a state that doesn't really make sense. Still, that quick fix probably helps in the attach case, since it avoids requiring symbols outside of libpthread, but I would just like to understand. Simon