From owner-svn-src-head@freebsd.org  Tue Jun 14 20:58:06 2016
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 7866CB72551;
 Tue, 14 Jun 2016 20:58:06 +0000 (UTC) (envelope-from np@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 3B13422D3;
 Tue, 14 Jun 2016 20:58:06 +0000 (UTC) (envelope-from np@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u5EKw5fC012794;
 Tue, 14 Jun 2016 20:58:05 GMT (envelope-from np@FreeBSD.org)
Received: (from np@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id u5EKw5ci012793;
 Tue, 14 Jun 2016 20:58:05 GMT (envelope-from np@FreeBSD.org)
Message-Id: <201606142058.u5EKw5ci012793@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: np set sender to np@FreeBSD.org
 using -f
From: Navdeep Parhar <np@FreeBSD.org>
Date: Tue, 14 Jun 2016 20:58:05 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r301896 - head/sys/ofed/drivers/infiniband/core
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: 2.1.22
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: Tue, 14 Jun 2016 20:58:06 -0000

Author: np
Date: Tue Jun 14 20:58:05 2016
New Revision: 301896
URL: https://svnweb.freebsd.org/changeset/base/301896

Log:
  Fix bug in iwcm that caused a panic in iw_cm_wq when krping is run
  repeatedly in a tight loop.
  
  Approved by:	re (gjb@)
  Obtained from:	hselasky@ (part of larger changes in D5791)

Modified:
  head/sys/ofed/drivers/infiniband/core/iwcm.c

Modified: head/sys/ofed/drivers/infiniband/core/iwcm.c
==============================================================================
--- head/sys/ofed/drivers/infiniband/core/iwcm.c	Tue Jun 14 18:41:18 2016	(r301895)
+++ head/sys/ofed/drivers/infiniband/core/iwcm.c	Tue Jun 14 20:58:05 2016	(r301896)
@@ -266,9 +266,16 @@ static void add_ref(struct iw_cm_id *cm_
 static void rem_ref(struct iw_cm_id *cm_id)
 {
 	struct iwcm_id_private *cm_id_priv;
+	int cb_destroy;
+
 	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
-	if (iwcm_deref_id(cm_id_priv) &&
-	    test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
+
+	/*
+	 * Test bit before deref in case the cm_id gets freed on another
+	 * thread.
+	 */
+	cb_destroy = test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
+	if (iwcm_deref_id(cm_id_priv) && cb_destroy) {
 		BUG_ON(!list_empty(&cm_id_priv->work_list));
 		free_cm_id(cm_id_priv);
 	}
@@ -1157,6 +1164,8 @@ static void cm_work_handler(struct work_
 			}
 			return;
 		}
+		if (empty)
+			return;
 		spin_lock_irqsave(&cm_id_priv->lock, flags);
 	}
 	spin_unlock_irqrestore(&cm_id_priv->lock, flags);