From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35270 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729661AbeJBURn (ORCPT ); Tue, 2 Oct 2018 16:17:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steve Wise , Jason Gunthorpe Subject: [PATCH 4.14 108/137] RDMA/uverbs: Atomically flush and mark closed the comp event queue Date: Tue, 2 Oct 2018 06:25:09 -0700 Message-Id: <20181002132506.066559052@linuxfoundation.org> In-Reply-To: <20181002132458.446916963@linuxfoundation.org> References: <20181002132458.446916963@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steve Wise commit 67e3816842fe6414d629c7515b955952ec40c7d7 upstream. Currently a uverbs completion event queue is flushed of events in ib_uverbs_comp_event_close() with the queue spinlock held and then released. Yet setting ev_queue->is_closed is not set until later in uverbs_hot_unplug_completion_event_file(). In between the time ib_uverbs_comp_event_close() releases the lock and uverbs_hot_unplug_completion_event_file() acquires the lock, a completion event can arrive and be inserted into the event queue by ib_uverbs_comp_handler(). This can cause a "double add" list_add warning or crash depending on the kernel configuration, or a memory leak because the event is never dequeued since the queue is already closed down. So add setting ev_queue->is_closed = 1 to ib_uverbs_comp_event_close(). Cc: stable@vger.kernel.org Fixes: 1e7710f3f656 ("IB/core: Change completion channel to use the reworked objects schema") Signed-off-by: Steve Wise Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/uverbs_main.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -424,6 +424,7 @@ static int ib_uverbs_comp_event_close(st list_del(&entry->obj_list); kfree(entry); } + file->ev_queue.is_closed = 1; spin_unlock_irq(&file->ev_queue.lock); uverbs_close_fd(filp);