From owner-svn-src-all@FreeBSD.ORG Sat Dec 20 22:12:05 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 657D638A; Sat, 20 Dec 2014 22:12:05 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 379792A7F; Sat, 20 Dec 2014 22:12:05 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id sBKMC572089035; Sat, 20 Dec 2014 22:12:05 GMT (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id sBKMC4FI089033; Sat, 20 Dec 2014 22:12:04 GMT (envelope-from glebius@FreeBSD.org) Message-Id: <201412202212.sBKMC4FI089033@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: glebius set sender to glebius@FreeBSD.org using -f From: Gleb Smirnoff Date: Sat, 20 Dec 2014 22:12:04 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r275968 - 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-all@freebsd.org X-Mailman-Version: 2.1.18-1 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: Sat, 20 Dec 2014 22:12:05 -0000 Author: glebius Date: Sat Dec 20 22:12:04 2014 New Revision: 275968 URL: https://svnweb.freebsd.org/changeset/base/275968 Log: Revert r274494, r274712, r275955 and provide extra comments explaining why there could appear a zero-sized mbufs in socket buffers. A proper fix would be to divorce record socket buffers and stream socket buffers, and divorce pru_send that accepts normal data from pru_send that accepts control data. Modified: head/sys/kern/uipc_sockbuf.c head/sys/kern/uipc_socket.c Modified: head/sys/kern/uipc_sockbuf.c ============================================================================== --- head/sys/kern/uipc_sockbuf.c Sat Dec 20 21:17:28 2014 (r275967) +++ head/sys/kern/uipc_sockbuf.c Sat Dec 20 22:12:04 2014 (r275968) @@ -640,9 +640,6 @@ sbappendstream_locked(struct sockbuf *sb { SOCKBUF_LOCK_ASSERT(sb); - if (m == NULL) - return; - KASSERT(m->m_nextpkt == NULL,("sbappendstream 0")); KASSERT(sb->sb_mb == sb->sb_lastrecord,("sbappendstream 1")); @@ -1065,6 +1062,21 @@ sbcut_internal(struct sockbuf *sb, int l m = n; } } + /* + * Free any zero-length mbufs from the buffer. + * For SOCK_DGRAM sockets such mbufs represent empty records. + * XXX: For SOCK_STREAM sockets such mbufs can appear in the buffer, + * when sosend_generic() needs to send only control data. + */ + while (m && m->m_len == 0) { + struct mbuf *n; + + sbfree(sb, m); + n = m->m_next; + m->m_next = mfree; + mfree = m; + m = n; + } if (m) { sb->sb_mb = m; m->m_nextpkt = next; Modified: head/sys/kern/uipc_socket.c ============================================================================== --- head/sys/kern/uipc_socket.c Sat Dec 20 21:17:28 2014 (r275967) +++ head/sys/kern/uipc_socket.c Sat Dec 20 22:12:04 2014 (r275968) @@ -1310,11 +1310,14 @@ restart: resid = 0; if (flags & MSG_EOR) top->m_flags |= M_EOR; - } else if (resid > 0) { + } else { /* * Copy the data from userland into a mbuf - * chain. If no data is to be copied in, - * a single empty mbuf is returned. + * chain. If resid is 0, which can happen + * only if we have control to send, then + * a single empty mbuf is returned. This + * is a workaround to prevent protocol send + * methods to panic. */ top = m_uiotombuf(uio, M_WAITOK, space, (atomic ? max_hdr : 0),