From owner-svn-src-head@freebsd.org  Thu Jun  8 06:16:48 2017
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 762B7BF7652;
 Thu,  8 Jun 2017 06:16:48 +0000 (UTC)
 (envelope-from glebius@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::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 4693F7603B;
 Thu,  8 Jun 2017 06:16:48 +0000 (UTC)
 (envelope-from glebius@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v586Glua020212;
 Thu, 8 Jun 2017 06:16:47 GMT (envelope-from glebius@FreeBSD.org)
Received: (from glebius@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id v586Glh8020211;
 Thu, 8 Jun 2017 06:16:47 GMT (envelope-from glebius@FreeBSD.org)
Message-Id: <201706080616.v586Glh8020211@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: glebius set sender to
 glebius@FreeBSD.org using -f
From: Gleb Smirnoff <glebius@FreeBSD.org>
Date: Thu, 8 Jun 2017 06:16:47 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r319685 - 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: 2.1.23
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 08 Jun 2017 06:16:48 -0000

Author: glebius
Date: Thu Jun  8 06:16:47 2017
New Revision: 319685
URL: https://svnweb.freebsd.org/changeset/base/319685

Log:
  Fix a degenerate case when soisdisconnected() would call soisconnected().
  
  This happens when closing a socket with upcall, and trace is: soclose()->
  ... protocol ... -> soisdisconnected() -> socantrcvmore_locked() ->
  sowakeup() -> soisconnected().
  
  Right now this case is innocent for two reasons.  First, soisconnected()
  doesn't clear SS_ISDISCONNECTED flag.  Second, the mutex to lock the
  socket is the socket receive buffer mutex, and sodisconnected() first
  disables the receive buffer. But in future code, the mutex to lock
  socket is different to buffer mutex, and we would get undesired mutex
  recursion.
  
  The fix is to check SS_ISDISCONNECTED flag before calling upcall.

Modified:
  head/sys/kern/uipc_sockbuf.c

Modified: head/sys/kern/uipc_sockbuf.c
==============================================================================
--- head/sys/kern/uipc_sockbuf.c	Thu Jun  8 06:13:53 2017	(r319684)
+++ head/sys/kern/uipc_sockbuf.c	Thu Jun  8 06:16:47 2017	(r319685)
@@ -322,7 +322,7 @@ sowakeup(struct socket *so, struct sockbuf *sb)
 		wakeup(&sb->sb_acc);
 	}
 	KNOTE_LOCKED(&sb->sb_sel.si_note, 0);
-	if (sb->sb_upcall != NULL) {
+	if (sb->sb_upcall != NULL && !(so->so_state & SS_ISDISCONNECTED)) {
 		ret = sb->sb_upcall(so, sb->sb_upcallarg, M_NOWAIT);
 		if (ret == SU_ISCONNECTED) {
 			KASSERT(sb == &so->so_rcv,