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 F0C20385840E for ; Thu, 11 Nov 2021 12:02:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org F0C20385840E 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-203-QKbJixeoMFOOoH0KYOWu0w-1; Thu, 11 Nov 2021 07:02:16 -0500 X-MC-Unique: QKbJixeoMFOOoH0KYOWu0w-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 873341006AA4; Thu, 11 Nov 2021 12:02:14 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.82]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9CDE45DA61; Thu, 11 Nov 2021 12:02:09 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Cc: libc-alpha@sourceware.org, John Mellor-Crummey , Ben Woodard , Vivek Das Mohapatra Subject: Re: [PATCH v5 04/22] elf: Suppress audit calls when a (new) namespace is empty (BZ #28062) References: <20211109183347.2943786-1-adhemerval.zanella@linaro.org> <20211109183347.2943786-5-adhemerval.zanella@linaro.org> <871r3o5c77.fsf@oldenburg.str.redhat.com> Date: Thu, 11 Nov 2021 13:02:07 +0100 In-Reply-To: (Adhemerval Zanella's message of "Thu, 11 Nov 2021 08:51:35 -0300") Message-ID: <87o86qzyrk.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 X-Spam-Status: No, score=-12.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP 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: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Nov 2021 12:02:23 -0000 * Adhemerval Zanella: > On 10/11/2021 11:15, Florian Weimer wrote: >> * Adhemerval Zanella: >> >>> diff --git a/elf/dl-load.c b/elf/dl-load.c >>> index 9f4fa9617d..72298776f6 100644 >>> --- a/elf/dl-load.c >>> +++ b/elf/dl-load.c >>> @@ -1067,8 +1067,11 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, >>> && __glibc_unlikely (GLRO(dl_naudit) > 0)) >>> { >>> struct link_map *head = GL(dl_ns)[nsid]._ns_loaded; >>> - /* Do not call the functions for any auditing object. */ >>> - if (head->l_auditing == 0) >>> + /* Do not call the functions for any auditing object and also do not >>> + try to call auditing functions if the namespace is currently >>> + empty. This happens when opening the first DSO in a new >>> + namespace. */ >>> + if (head != NULL && head->l_auditing == 0) >>> { >>> struct audit_ifaces *afct = GLRO(dl_audit); >>> for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) >> >> As far as I can tell, using GL(dl_ns)[nsid]._ns_loaded for la_activity >> is a completely arbitrary choice. I think we should use >> &GL(dl_ns)[nsid] for secondary namespace instead, and keep >> GL(dl_ns)[LM_ID_BASE]._ns_loaded for backwards compatibility. >> >> This will allow us to generate an LA_ACT_ADD event for an empty >> namespace. > > I am not really following you here, '&GL(dl_ns)[nsid]' is just the container > here, we need to iterate over the 'link_maps' within it. Hmm. I had a peeked at the Solaris documentation, and it says that LA_ACT_ADD uses the head link map of the namespace as a cookie. I really dislike that we produce a LA_ACT_DELETE without the corresponding LA_ACT_ADD due to this issue. Can we use the link map allocated used _dl_new_object as the cookie if the namespace is empty? This seems like the right thing to do here. The allocation happens just a few lines further down. Thanks, Florian