From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760557Ab2BJWlM (ORCPT ); Fri, 10 Feb 2012 17:41:12 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:50022 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760537Ab2BJWlI (ORCPT ); Fri, 10 Feb 2012 17:41:08 -0500 MIME-Version: 1.0 Message-Id: <20120210222946.999041733@clark.kroah.org> User-Agent: quilt/0.51-15.1 Date: Fri, 10 Feb 2012 14:29:41 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Bernd Schubert , Sven Breuner , Sean Hefty , Roland Dreier Subject: [patch 22/86] RDMA/core: Fix kernel panic by always initializing qp->usecnt In-Reply-To: <20120210223514.GA24190@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bernd Schubert commit e47e321a35c741ee41b67976f8c6a3a7a42bc5c0 upstream. We have just been investigating kernel panics related to cq->ibcq.event_handler() completion calls. The problem is that ib_destroy_qp() fails with -EBUSY. Further investigation revealed qp->usecnt is not initialized. This counter was introduced in linux-3.2 by commit 0e0ec7e0638e ("RDMA/core: Export ib_open_qp() to share XRC TGT QPs") but it only gets initialized for IB_QPT_XRC_TGT, but it is checked in ib_destroy_qp() for any QP type. Fix this by initializing qp->usecnt for every QP we create. Signed-off-by: Bernd Schubert Signed-off-by: Sven Breuner [ Initialize qp->usecnt in uverbs too. - Sean ] Signed-off-by: Sean Hefty Signed-off-by: Roland Dreier Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/uverbs_cmd.c | 1 + drivers/infiniband/core/verbs.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -1485,6 +1485,7 @@ ssize_t ib_uverbs_create_qp(struct ib_uv qp->event_handler = attr.event_handler; qp->qp_context = attr.qp_context; qp->qp_type = attr.qp_type; + atomic_set(&qp->usecnt, 0); atomic_inc(&pd->usecnt); atomic_inc(&attr.send_cq->usecnt); if (attr.recv_cq) --- a/drivers/infiniband/core/verbs.c +++ b/drivers/infiniband/core/verbs.c @@ -421,6 +421,7 @@ struct ib_qp *ib_create_qp(struct ib_pd qp->uobject = NULL; qp->qp_type = qp_init_attr->qp_type; + atomic_set(&qp->usecnt, 0); if (qp_init_attr->qp_type == IB_QPT_XRC_TGT) { qp->event_handler = __ib_shared_qp_event_handler; qp->qp_context = qp; @@ -430,7 +431,6 @@ struct ib_qp *ib_create_qp(struct ib_pd qp->xrcd = qp_init_attr->xrcd; atomic_inc(&qp_init_attr->xrcd->usecnt); INIT_LIST_HEAD(&qp->open_list); - atomic_set(&qp->usecnt, 0); real_qp = qp; qp = __ib_open_qp(real_qp, qp_init_attr->event_handler,