From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85309C64E7B for ; Tue, 1 Dec 2020 08:56:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 290062220B for ; Tue, 1 Dec 2020 08:56:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="WeFyMXXo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387617AbgLAI4A (ORCPT ); Tue, 1 Dec 2020 03:56:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:58748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387595AbgLAIzx (ORCPT ); Tue, 1 Dec 2020 03:55:53 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F37F12223F; Tue, 1 Dec 2020 08:55:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606812912; bh=S+18DW3RWsDkFAZ23f5RlVDOPNUV8uvTQoe1C2dAA+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WeFyMXXoPR9+cLxWctRpwxJc/c7ey/LS2unJBSH6ezZOxAfrbPzzwhOh7cFuQ2Fmj urD1lHVUxTQ4f/RE/lNhxt4R9NRNSkMg6GUuCn4jPnAcPzRCepIBO6k2emVro59TSj klvyAkSWAfa61+Eo4/F3o28zbxy4DySnVf21pU7I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maurizio Lombardi , Mike Christie , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.9 19/42] scsi: target: iscsi: Fix cmd abort fabric stop race Date: Tue, 1 Dec 2020 09:53:17 +0100 Message-Id: <20201201084643.482426287@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201201084642.194933793@linuxfoundation.org> References: <20201201084642.194933793@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mike Christie [ Upstream commit f36199355c64a39fe82cfddc7623d827c7e050da ] Maurizio found a race where the abort and cmd stop paths can race as follows: 1. thread1 runs iscsit_release_commands_from_conn and sets CMD_T_FABRIC_STOP. 2. thread2 runs iscsit_aborted_task and then does __iscsit_free_cmd. It then returns from the aborted_task callout and we finish target_handle_abort and do: target_handle_abort -> transport_cmd_check_stop_to_fabric -> lio_check_stop_free -> target_put_sess_cmd The cmd is now freed. 3. thread1 now finishes iscsit_release_commands_from_conn and runs iscsit_free_cmd while accessing a command we just released. In __target_check_io_state we check for CMD_T_FABRIC_STOP and set the CMD_T_ABORTED if the driver is not cleaning up the cmd because of a session shutdown. However, iscsit_release_commands_from_conn only sets the CMD_T_FABRIC_STOP and does not check to see if the abort path has claimed completion ownership of the command. This adds a check in iscsit_release_commands_from_conn so only the abort or fabric stop path cleanup the command. Link: https://lore.kernel.org/r/1605318378-9269-1-git-send-email-michael.christie@oracle.com Reported-by: Maurizio Lombardi Reviewed-by: Maurizio Lombardi Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/iscsi/iscsi_target.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 7c0f4b96816a8..eba21f06a9b95 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -493,8 +493,7 @@ void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd) bool scsi_cmd = (cmd->iscsi_opcode == ISCSI_OP_SCSI_CMD); spin_lock_bh(&conn->cmd_lock); - if (!list_empty(&cmd->i_conn_node) && - !(cmd->se_cmd.transport_state & CMD_T_FABRIC_STOP)) + if (!list_empty(&cmd->i_conn_node)) list_del_init(&cmd->i_conn_node); spin_unlock_bh(&conn->cmd_lock); @@ -4093,12 +4092,22 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn) spin_lock_bh(&conn->cmd_lock); list_splice_init(&conn->conn_cmd_list, &tmp_list); - list_for_each_entry(cmd, &tmp_list, i_conn_node) { + list_for_each_entry_safe(cmd, cmd_tmp, &tmp_list, i_conn_node) { struct se_cmd *se_cmd = &cmd->se_cmd; if (se_cmd->se_tfo != NULL) { spin_lock_irq(&se_cmd->t_state_lock); - se_cmd->transport_state |= CMD_T_FABRIC_STOP; + if (se_cmd->transport_state & CMD_T_ABORTED) { + /* + * LIO's abort path owns the cleanup for this, + * so put it back on the list and let + * aborted_task handle it. + */ + list_move_tail(&cmd->i_conn_node, + &conn->conn_cmd_list); + } else { + se_cmd->transport_state |= CMD_T_FABRIC_STOP; + } spin_unlock_irq(&se_cmd->t_state_lock); } } -- 2.27.0