Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993913AbbHHWXg (ORCPT ); Sat, 8 Aug 2015 18:23:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36799 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993879AbbHHWX3 (ORCPT ); Sat, 8 Aug 2015 18:23:29 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sagi Grimberg , Nicholas Bellinger Subject: [PATCH 4.1 110/123] iscsi-target: Fix iscsit_start_kthreads failure OOPs Date: Sat, 8 Aug 2015 15:09:48 -0700 Message-Id: <20150808220721.476145831@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150808220717.771230091@linuxfoundation.org> References: <20150808220717.771230091@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 Content-Length: 9784 Lines: 305 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Bellinger commit e54198657b65625085834847ab6271087323ffea upstream. This patch fixes a regression introduced with the following commit in v4.0-rc1 code, where a iscsit_start_kthreads() failure triggers a NULL pointer dereference OOPs: commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca Author: Nicholas Bellinger Date: Thu Feb 26 22:19:15 2015 -0800 iscsi-target: Convert iscsi_thread_set usage to kthread.h To address this bug, move iscsit_start_kthreads() immediately preceeding the transmit of last login response, before signaling a successful transition into full-feature-phase within existing iscsi_target_do_tx_login_io() logic. This ensures that no target-side resource allocation failures can occur after the final login response has been successfully sent. Also, it adds a iscsi_conn->rx_login_comp to allow the RX thread to sleep to prevent other socket related failures until the final iscsi_post_login_handler() call is able to complete. Cc: Sagi Grimberg Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target.c | 18 ++++++++++-- drivers/target/iscsi/iscsi_target_login.c | 45 +++++++++++------------------- drivers/target/iscsi/iscsi_target_login.h | 3 +- drivers/target/iscsi/iscsi_target_nego.c | 34 ++++++++++++++++++++++ include/target/iscsi/iscsi_target_core.h | 1 5 files changed, 68 insertions(+), 33 deletions(-) --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4001,7 +4001,13 @@ get_immediate: } transport_err: - iscsit_take_action_for_connection_exit(conn); + /* + * Avoid the normal connection failure code-path if this connection + * is still within LOGIN mode, and iscsi_np process context is + * responsible for cleaning up the early connection failure. + */ + if (conn->conn_state != TARG_CONN_STATE_IN_LOGIN) + iscsit_take_action_for_connection_exit(conn); out: return 0; } @@ -4093,7 +4099,7 @@ reject: int iscsi_target_rx_thread(void *arg) { - int ret; + int ret, rc; u8 buffer[ISCSI_HDR_LEN], opcode; u32 checksum = 0, digest = 0; struct iscsi_conn *conn = arg; @@ -4103,10 +4109,16 @@ int iscsi_target_rx_thread(void *arg) * connection recovery / failure event can be triggered externally. */ allow_signal(SIGINT); + /* + * Wait for iscsi_post_login_handler() to complete before allowing + * incoming iscsi/tcp socket I/O, and/or failing the connection. + */ + rc = wait_for_completion_interruptible(&conn->rx_login_comp); + if (rc < 0) + return 0; if (conn->conn_transport->transport_type == ISCSI_INFINIBAND) { struct completion comp; - int rc; init_completion(&comp); rc = wait_for_completion_interruptible(&comp); --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -82,6 +82,7 @@ static struct iscsi_login *iscsi_login_i init_completion(&conn->conn_logout_comp); init_completion(&conn->rx_half_close_comp); init_completion(&conn->tx_half_close_comp); + init_completion(&conn->rx_login_comp); spin_lock_init(&conn->cmd_lock); spin_lock_init(&conn->conn_usage_lock); spin_lock_init(&conn->immed_queue_lock); @@ -699,7 +700,7 @@ static void iscsi_post_login_start_timer iscsit_start_nopin_timer(conn); } -static int iscsit_start_kthreads(struct iscsi_conn *conn) +int iscsit_start_kthreads(struct iscsi_conn *conn) { int ret = 0; @@ -734,6 +735,7 @@ static int iscsit_start_kthreads(struct return 0; out_tx: + send_sig(SIGINT, conn->tx_thread, 1); kthread_stop(conn->tx_thread); conn->tx_thread_active = false; out_bitmap: @@ -744,7 +746,7 @@ out_bitmap: return ret; } -int iscsi_post_login_handler( +void iscsi_post_login_handler( struct iscsi_np *np, struct iscsi_conn *conn, u8 zero_tsih) @@ -754,7 +756,6 @@ int iscsi_post_login_handler( struct se_session *se_sess = sess->se_sess; struct iscsi_portal_group *tpg = sess->tpg; struct se_portal_group *se_tpg = &tpg->tpg_se_tpg; - int rc; iscsit_inc_conn_usage_count(conn); @@ -795,10 +796,6 @@ int iscsi_post_login_handler( sess->sess_ops->InitiatorName); spin_unlock_bh(&sess->conn_lock); - rc = iscsit_start_kthreads(conn); - if (rc) - return rc; - iscsi_post_login_start_timers(conn); /* * Determine CPU mask to ensure connection's RX and TX kthreads @@ -807,15 +804,20 @@ int iscsi_post_login_handler( iscsit_thread_get_cpumask(conn); conn->conn_rx_reset_cpumask = 1; conn->conn_tx_reset_cpumask = 1; - + /* + * Wakeup the sleeping iscsi_target_rx_thread() now that + * iscsi_conn is in TARG_CONN_STATE_LOGGED_IN state. + */ + complete(&conn->rx_login_comp); iscsit_dec_conn_usage_count(conn); + if (stop_timer) { spin_lock_bh(&se_tpg->session_lock); iscsit_stop_time2retain_timer(sess); spin_unlock_bh(&se_tpg->session_lock); } iscsit_dec_session_usage_count(sess); - return 0; + return; } iscsi_set_session_parameters(sess->sess_ops, conn->param_list, 1); @@ -856,10 +858,6 @@ int iscsi_post_login_handler( " iSCSI Target Portal Group: %hu\n", tpg->nsessions, tpg->tpgt); spin_unlock_bh(&se_tpg->session_lock); - rc = iscsit_start_kthreads(conn); - if (rc) - return rc; - iscsi_post_login_start_timers(conn); /* * Determine CPU mask to ensure connection's RX and TX kthreads @@ -868,10 +866,12 @@ int iscsi_post_login_handler( iscsit_thread_get_cpumask(conn); conn->conn_rx_reset_cpumask = 1; conn->conn_tx_reset_cpumask = 1; - + /* + * Wakeup the sleeping iscsi_target_rx_thread() now that + * iscsi_conn is in TARG_CONN_STATE_LOGGED_IN state. + */ + complete(&conn->rx_login_comp); iscsit_dec_conn_usage_count(conn); - - return 0; } static void iscsi_handle_login_thread_timeout(unsigned long data) @@ -1436,23 +1436,12 @@ static int __iscsi_target_login_thread(s if (ret < 0) goto new_sess_out; - if (!conn->sess) { - pr_err("struct iscsi_conn session pointer is NULL!\n"); - goto new_sess_out; - } - iscsi_stop_login_thread_timer(np); - if (signal_pending(current)) - goto new_sess_out; - if (ret == 1) { tpg_np = conn->tpg_np; - ret = iscsi_post_login_handler(np, conn, zero_tsih); - if (ret < 0) - goto new_sess_out; - + iscsi_post_login_handler(np, conn, zero_tsih); iscsit_deaccess_np(np, tpg, tpg_np); } --- a/drivers/target/iscsi/iscsi_target_login.h +++ b/drivers/target/iscsi/iscsi_target_login.h @@ -12,7 +12,8 @@ extern int iscsit_accept_np(struct iscsi extern int iscsit_get_login_rx(struct iscsi_conn *, struct iscsi_login *); extern int iscsit_put_login_tx(struct iscsi_conn *, struct iscsi_login *, u32); extern void iscsit_free_conn(struct iscsi_np *, struct iscsi_conn *); -extern int iscsi_post_login_handler(struct iscsi_np *, struct iscsi_conn *, u8); +extern int iscsit_start_kthreads(struct iscsi_conn *); +extern void iscsi_post_login_handler(struct iscsi_np *, struct iscsi_conn *, u8); extern void iscsi_target_login_sess_out(struct iscsi_conn *, struct iscsi_np *, bool, bool); extern int iscsi_target_login_thread(void *); --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -17,6 +17,7 @@ ******************************************************************************/ #include +#include #include #include #include @@ -361,10 +362,24 @@ static int iscsi_target_do_tx_login_io(s ntohl(login_rsp->statsn), login->rsp_length); padding = ((-login->rsp_length) & 3); + /* + * Before sending the last login response containing the transition + * bit for full-feature-phase, go ahead and start up TX/RX threads + * now to avoid potential resource allocation failures after the + * final login response has been sent. + */ + if (login->login_complete) { + int rc = iscsit_start_kthreads(conn); + if (rc) { + iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR, + ISCSI_LOGIN_STATUS_NO_RESOURCES); + return -1; + } + } if (conn->conn_transport->iscsit_put_login_tx(conn, login, login->rsp_length + padding) < 0) - return -1; + goto err; login->rsp_length = 0; mutex_lock(&sess->cmdsn_mutex); @@ -373,6 +388,23 @@ static int iscsi_target_do_tx_login_io(s mutex_unlock(&sess->cmdsn_mutex); return 0; + +err: + if (login->login_complete) { + if (conn->rx_thread && conn->rx_thread_active) { + send_sig(SIGINT, conn->rx_thread, 1); + kthread_stop(conn->rx_thread); + } + if (conn->tx_thread && conn->tx_thread_active) { + send_sig(SIGINT, conn->tx_thread, 1); + kthread_stop(conn->tx_thread); + } + spin_lock(&iscsit_global->ts_bitmap_lock); + bitmap_release_region(iscsit_global->ts_bitmap, conn->bitmap_id, + get_order(1)); + spin_unlock(&iscsit_global->ts_bitmap_lock); + } + return -1; } static void iscsi_target_sk_data_ready(struct sock *sk) --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -606,6 +606,7 @@ struct iscsi_conn { int bitmap_id; int rx_thread_active; struct task_struct *rx_thread; + struct completion rx_login_comp; int tx_thread_active; struct task_struct *tx_thread; /* list_head for session connection list */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/