From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767993AbcHROQ6 (ORCPT ); Thu, 18 Aug 2016 10:16:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37539 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1950484AbcHROQ1 (ORCPT ); Thu, 18 Aug 2016 10:16:27 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Christie , Quinn Tran , Himanshu Madhani , Christoph Hellwig , Hannes Reinecke , Nicholas Bellinger Subject: [PATCH 4.7 166/186] target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP Date: Thu, 18 Aug 2016 15:59:43 +0200 Message-Id: <20160818135939.327327189@linuxfoundation.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160818135932.219369981@linuxfoundation.org> References: <20160818135932.219369981@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Bellinger commit 5e2c956b8aa24d4f33ff7afef92d409eed164746 upstream. During transport_generic_free_cmd() with a concurrent TMR ABORT_TASK and shutdown CMD_T_FABRIC_STOP bit set, the caller will be blocked on se_cmd->cmd_wait_stop completion until the final kref_put() -> target_release_cmd_kref() has been invoked to call complete(). However, when ABORT_TASK is completed with FUNCTION_COMPLETE in core_tmr_abort_task(), the aborted se_cmd will have already been removed from se_sess->sess_cmd_list via list_del_init(). This results in target_release_cmd_kref() hitting the legacy list_empty() == true check, invoking ->release_cmd() but skipping complete() to wakeup se_cmd->cmd_wait_stop blocked earlier in transport_generic_free_cmd() code. To address this bug, it's safe to go ahead and drop the original list_empty() check so that fabric_stop invokes the complete() as expected, since list_del_init() can safely be used on a empty list. Cc: Mike Christie Cc: Quinn Tran Cc: Himanshu Madhani Cc: Christoph Hellwig Cc: Hannes Reinecke Tested-by: Nicholas Bellinger Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_transport.c | 6 ------ 1 file changed, 6 deletions(-) --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2565,12 +2565,6 @@ static void target_release_cmd_kref(stru bool fabric_stop; spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - if (list_empty(&se_cmd->se_cmd_list)) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); - target_free_cmd_mem(se_cmd); - se_cmd->se_tfo->release_cmd(se_cmd); - return; - } spin_lock(&se_cmd->t_state_lock); fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);