From owner-svn-src-all@FreeBSD.ORG Thu Oct 30 23:09:20 2008 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 71F7E1065675; Thu, 30 Oct 2008 23:09:20 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 52D398FC1A; Thu, 30 Oct 2008 23:09:20 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id m9UN9K8M063984; Thu, 30 Oct 2008 23:09:20 GMT (envelope-from rwatson@svn.freebsd.org) Received: (from rwatson@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id m9UN9KdY063983; Thu, 30 Oct 2008 23:09:20 GMT (envelope-from rwatson@svn.freebsd.org) Message-Id: <200810302309.m9UN9KdY063983@svn.freebsd.org> From: Robert Watson Date: Thu, 30 Oct 2008 23:09:20 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r184489 - head/sys/security/audit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Oct 2008 23:09:20 -0000 Author: rwatson Date: Thu Oct 30 23:09:19 2008 New Revision: 184489 URL: http://svn.freebsd.org/changeset/base/184489 Log: When we drop an audit record going to and audit pipe because the audit pipe has overflowed, drop the newest, rather than oldest, record. This makes overflow drop behavior consistent with memory allocation failure leading to drop, avoids touching the consumer end of the queue from a producer, and lowers the CPU overhead of dropping a record by dropping before memory allocation and copying. Obtained from: Apple, Inc. MFC after: 2 months Modified: head/sys/security/audit/audit_pipe.c Modified: head/sys/security/audit/audit_pipe.c ============================================================================== --- head/sys/security/audit/audit_pipe.c Thu Oct 30 21:58:39 2008 (r184488) +++ head/sys/security/audit/audit_pipe.c Thu Oct 30 23:09:19 2008 (r184489) @@ -424,17 +424,22 @@ audit_pipe_preselect(au_id_t auid, au_ev /* * Append individual record to a queue -- allocate queue-local buffer, and - * add to the queue. We try to drop from the head of the queue so that more - * recent events take precedence over older ones, but if allocation fails we - * do drop the new event. + * add to the queue. If the queue is full or we can't allocate memory, drop + * the newest record. */ static void audit_pipe_append(struct audit_pipe *ap, void *record, u_int record_len) { - struct audit_pipe_entry *ape, *ape_remove; + struct audit_pipe_entry *ape; AUDIT_PIPE_LOCK_ASSERT(ap); + if (ap->ap_qlen >= ap->ap_qlimit) { + ap->ap_drops++; + audit_pipe_drops++; + return; + } + ape = malloc(sizeof(*ape), M_AUDIT_PIPE_ENTRY, M_NOWAIT | M_ZERO); if (ape == NULL) { ap->ap_drops++; @@ -453,15 +458,6 @@ audit_pipe_append(struct audit_pipe *ap, bcopy(record, ape->ape_record, record_len); ape->ape_record_len = record_len; - if (ap->ap_qlen >= ap->ap_qlimit) { - ape_remove = TAILQ_FIRST(&ap->ap_queue); - TAILQ_REMOVE(&ap->ap_queue, ape_remove, ape_queue); - audit_pipe_entry_free(ape_remove); - ap->ap_qlen--; - ap->ap_drops++; - audit_pipe_drops++; - } - TAILQ_INSERT_TAIL(&ap->ap_queue, ape, ape_queue); ap->ap_inserts++; ap->ap_qlen++;