From patchwork Mon Aug 7 03:25:32 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. Bellinger" X-Patchwork-Id: 9884361 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8C308602CC for ; Mon, 7 Aug 2017 03:19:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 814722856B for ; Mon, 7 Aug 2017 03:19:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7612828573; Mon, 7 Aug 2017 03:19:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02ECE2856B for ; Mon, 7 Aug 2017 03:19:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751425AbdHGDTm (ORCPT ); Sun, 6 Aug 2017 23:19:42 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:38747 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442AbdHGDTh (ORCPT ); Sun, 6 Aug 2017 23:19:37 -0400 Received: from linux-iscsi.org (localhost [127.0.0.1]) by linux-iscsi.org (Postfix) with ESMTP id 7B24B40B27; Mon, 7 Aug 2017 03:25:40 +0000 (UTC) From: "Nicholas A. Bellinger" To: target-devel Cc: stable , Sasha Levin , Greg-KH , Jiang Yi Subject: [PATCH-v4.1.y 4/7] iscsi-target: Always wait for kthread_should_stop() before kthread exit Date: Mon, 7 Aug 2017 03:25:32 +0000 Message-Id: <1502076335-20271-5-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1502076335-20271-1-git-send-email-nab@linux-iscsi.org> References: <1502076335-20271-1-git-send-email-nab@linux-iscsi.org> Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jiang Yi commit 5e0cf5e6c43b9e19fc0284f69e5cd2b4a47523b0 upstream. There are three timing problems in the kthread usages of iscsi_target_mod: - np_thread of struct iscsi_np - rx_thread and tx_thread of struct iscsi_conn In iscsit_close_connection(), it calls send_sig(SIGINT, conn->tx_thread, 1); kthread_stop(conn->tx_thread); In conn->tx_thread, which is iscsi_target_tx_thread(), when it receive SIGINT the kthread will exit without checking the return value of kthread_should_stop(). So if iscsi_target_tx_thread() exit right between send_sig(SIGINT...) and kthread_stop(...), the kthread_stop() will try to stop an already stopped kthread. This is invalid according to the documentation of kthread_stop(). (Fix -ECONNRESET logout handling in iscsi_target_tx_thread and early iscsi_target_rx_thread failure case - nab) Signed-off-by: Jiang Yi Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target.c | 28 ++++++++++++++++++++++------ drivers/target/iscsi/iscsi_target_erl0.c | 6 +++++- drivers/target/iscsi/iscsi_target_erl0.h | 2 +- drivers/target/iscsi/iscsi_target_login.c | 4 ++++ 4 files changed, 32 insertions(+), 8 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index c65280d..696bf57 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -3967,6 +3967,8 @@ int iscsi_target_tx_thread(void *arg) { int ret = 0; struct iscsi_conn *conn = arg; + bool conn_freed = false; + /* * Allow ourselves to be interrupted by SIGINT so that a * connection recovery / failure event can be triggered externally. @@ -3992,12 +3994,14 @@ get_immediate: goto transport_err; ret = iscsit_handle_response_queue(conn); - if (ret == 1) + if (ret == 1) { goto get_immediate; - else if (ret == -ECONNRESET) + } else if (ret == -ECONNRESET) { + conn_freed = true; goto out; - else if (ret < 0) + } else if (ret < 0) { goto transport_err; + } } transport_err: @@ -4007,8 +4011,13 @@ transport_err: * responsible for cleaning up the early connection failure. */ if (conn->conn_state != TARG_CONN_STATE_IN_LOGIN) - iscsit_take_action_for_connection_exit(conn); + iscsit_take_action_for_connection_exit(conn, &conn_freed); out: + if (!conn_freed) { + while (!kthread_should_stop()) { + msleep(100); + } + } return 0; } @@ -4115,6 +4124,7 @@ int iscsi_target_rx_thread(void *arg) u32 checksum = 0, digest = 0; struct iscsi_conn *conn = arg; struct kvec iov; + bool conn_freed = false; /* * Allow ourselves to be interrupted by SIGINT so that a * connection recovery / failure event can be triggered externally. @@ -4126,7 +4136,7 @@ int iscsi_target_rx_thread(void *arg) */ rc = wait_for_completion_interruptible(&conn->rx_login_comp); if (rc < 0 || iscsi_target_check_conn_state(conn)) - return 0; + goto out; if (conn->conn_transport->transport_type == ISCSI_INFINIBAND) { struct completion comp; @@ -4211,7 +4221,13 @@ int iscsi_target_rx_thread(void *arg) transport_err: if (!signal_pending(current)) atomic_set(&conn->transport_failed, 1); - iscsit_take_action_for_connection_exit(conn); + iscsit_take_action_for_connection_exit(conn, &conn_freed); +out: + if (!conn_freed) { + while (!kthread_should_stop()) { + msleep(100); + } + } return 0; } diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c index 959a14c..6011644 100644 --- a/drivers/target/iscsi/iscsi_target_erl0.c +++ b/drivers/target/iscsi/iscsi_target_erl0.c @@ -930,8 +930,10 @@ static void iscsit_handle_connection_cleanup(struct iscsi_conn *conn) } } -void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn) +void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn, bool *conn_freed) { + *conn_freed = false; + spin_lock_bh(&conn->state_lock); if (atomic_read(&conn->connection_exit)) { spin_unlock_bh(&conn->state_lock); @@ -942,6 +944,7 @@ void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn) if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT) { spin_unlock_bh(&conn->state_lock); iscsit_close_connection(conn); + *conn_freed = true; return; } @@ -955,6 +958,7 @@ void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn) spin_unlock_bh(&conn->state_lock); iscsit_handle_connection_cleanup(conn); + *conn_freed = true; } /* diff --git a/drivers/target/iscsi/iscsi_target_erl0.h b/drivers/target/iscsi/iscsi_target_erl0.h index 21acc9a..42673fb 100644 --- a/drivers/target/iscsi/iscsi_target_erl0.h +++ b/drivers/target/iscsi/iscsi_target_erl0.h @@ -9,7 +9,7 @@ extern int iscsit_stop_time2retain_timer(struct iscsi_session *); extern void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *); extern void iscsit_cause_connection_reinstatement(struct iscsi_conn *, int); extern void iscsit_fall_back_to_erl0(struct iscsi_session *); -extern void iscsit_take_action_for_connection_exit(struct iscsi_conn *); +extern void iscsit_take_action_for_connection_exit(struct iscsi_conn *, bool *); extern int iscsit_recover_from_unknown_opcode(struct iscsi_conn *); #endif /*** ISCSI_TARGET_ERL0_H ***/ diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index c5cbd70..9e5793b 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -1507,5 +1507,9 @@ int iscsi_target_login_thread(void *arg) break; } + while (!kthread_should_stop()) { + msleep(100); + } + return 0; }