From owner-svn-src-head@FreeBSD.ORG Tue Nov 27 20:04:53 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id F238F9D0; Tue, 27 Nov 2012 20:04:52 +0000 (UTC) (envelope-from andre@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id BD6D28FC13; Tue, 27 Nov 2012 20:04:52 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.5/8.14.5) with ESMTP id qARK4qHT047210; Tue, 27 Nov 2012 20:04:52 GMT (envelope-from andre@svn.freebsd.org) Received: (from andre@localhost) by svn.freebsd.org (8.14.5/8.14.5/Submit) id qARK4qS8047209; Tue, 27 Nov 2012 20:04:52 GMT (envelope-from andre@svn.freebsd.org) Message-Id: <201211272004.qARK4qS8047209@svn.freebsd.org> From: Andre Oppermann Date: Tue, 27 Nov 2012 20:04:52 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r243627 - head/sys/kern X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Nov 2012 20:04:53 -0000 Author: andre Date: Tue Nov 27 20:04:52 2012 New Revision: 243627 URL: http://svnweb.freebsd.org/changeset/base/243627 Log: Fix a race on listen socket teardown where while draining the accept queues a new socket/connection may be added to the queue due to a race on the ACCEPT_LOCK. The submitted patch is slightly changed in comments, teardown and locking order and extended with KASSERT's. Submitted by: Vijay Singh Found by: His team. MFC after: 1 week Modified: head/sys/kern/uipc_socket.c Modified: head/sys/kern/uipc_socket.c ============================================================================== --- head/sys/kern/uipc_socket.c Tue Nov 27 19:35:21 2012 (r243626) +++ head/sys/kern/uipc_socket.c Tue Nov 27 20:04:52 2012 (r243627) @@ -555,6 +555,16 @@ sonewconn(struct socket *head, int conns so->so_snd.sb_flags |= head->so_snd.sb_flags & SB_AUTOSIZE; so->so_state |= connstatus; ACCEPT_LOCK(); + /* + * The accept socket may be tearing down but we just + * won a race on the ACCEPT_LOCK. + */ + if (!(so->so_options & SO_ACCEPTCONN)) { + SOCK_LOCK(so); + so->so_head = NULL; + sofree(so); /* NB: returns ACCEPT_UNLOCK'ed. */ + return (NULL); + } if (connstatus) { TAILQ_INSERT_TAIL(&head->so_comp, so, so_list); so->so_qstate |= SQ_COMP; @@ -780,9 +790,14 @@ soclose(struct socket *so) drop: if (so->so_proto->pr_usrreqs->pru_close != NULL) (*so->so_proto->pr_usrreqs->pru_close)(so); + ACCEPT_LOCK(); if (so->so_options & SO_ACCEPTCONN) { struct socket *sp; - ACCEPT_LOCK(); + /* + * Prevent new additions to the accept queues due + * to ACCEPT_LOCK races while we are draining them. + */ + so->so_options &= ~SO_ACCEPTCONN; while ((sp = TAILQ_FIRST(&so->so_incomp)) != NULL) { TAILQ_REMOVE(&so->so_incomp, sp, so_list); so->so_incqlen--; @@ -801,13 +816,15 @@ drop: soabort(sp); ACCEPT_LOCK(); } - ACCEPT_UNLOCK(); + KASSERT((TAILQ_EMPTY(&so->so_comp)), + ("%s: so_comp populated", __func__)); + KASSERT((TAILQ_EMPTY(&so->so_incomp)), + ("%s: so_incomp populated", __func__)); } - ACCEPT_LOCK(); SOCK_LOCK(so); KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF")); so->so_state |= SS_NOFDREF; - sorele(so); + sorele(so); /* NB: Returns with ACCEPT_UNLOCK(). */ CURVNET_RESTORE(); return (error); }