From patchwork Tue Dec 1 08:53:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 335750 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 5BB84C64E7B for ; Tue, 1 Dec 2020 09:28:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDCFE21D7F for ; Tue, 1 Dec 2020 09:28:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="a4Zjss3x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387829AbgLAJAw (ORCPT ); Tue, 1 Dec 2020 04:00:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:36612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388388AbgLAJAn (ORCPT ); Tue, 1 Dec 2020 04:00:43 -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 AAA6B21D46; Tue, 1 Dec 2020 09:00:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606813228; bh=xRhEKCxH1itKE1wlM/YR80gfrAOlSyTV8ixtllnBiPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a4Zjss3x65dWQbvSOygEcEm8fudd1SCm7DXMISqOlW1EFCpO1uXan80wjBoLyP0Rs WVXd2Af8KxyxnmMeXnX9MRKOucJXqaqacbbpdd3iJT8oCNAWOu0DbgQSBEOl/lwFwd AAPqUJl2cMyHBLw79veEs3NxjllyfIFE7cwtYtWs= 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 4.19 25/57] scsi: target: iscsi: Fix cmd abort fabric stop race Date: Tue, 1 Dec 2020 09:53:30 +0100 Message-Id: <20201201084650.410035711@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201201084647.751612010@linuxfoundation.org> References: <20201201084647.751612010@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 2602b57936d4b..58ccded1be857 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -492,8 +492,7 @@ EXPORT_SYMBOL(iscsit_queue_rsp); void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *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); @@ -4054,12 +4053,22 @@ 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); } }