From e54198657b65625085834847ab6271087323ffea Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Wed, 22 Jul 2015 23:14:19 -0700 Subject: [PATCH] iscsi-target: Fix iscsit_start_kthreads failure OOPs 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 Cc: # v3.10+ Signed-off-by: Nicholas Bellinger --- 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(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index afab32376126..202a42858f25 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -3998,7 +3998,13 @@ 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; } @@ -4082,7 +4088,7 @@ 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; @@ -4092,10 +4098,16 @@ 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); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index 3d0fe4ff5590..7e8f65e5448f 100644 --- 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_init_conn(struct iscsi_conn *conn) 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); @@ -644,7 +645,7 @@ static void iscsi_post_login_start_timers(struct iscsi_conn *conn) 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; @@ -679,6 +680,7 @@ static int iscsit_start_kthreads(struct iscsi_conn *conn) return 0; out_tx: + send_sig(SIGINT, conn->tx_thread, 1); kthread_stop(conn->tx_thread); conn->tx_thread_active = false; out_bitmap: @@ -689,7 +691,7 @@ 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) @@ -699,7 +701,6 @@ 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); @@ -739,10 +740,6 @@ 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 @@ -751,15 +748,20 @@ 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); @@ -800,10 +802,6 @@ 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 @@ -812,10 +810,12 @@ 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) @@ -1380,23 +1380,12 @@ static int __iscsi_target_login_thread(struct iscsi_np *np) 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); } diff --git a/drivers/target/iscsi/iscsi_target_login.h b/drivers/target/iscsi/iscsi_target_login.h index 1c7358081533..57aa0d0fd820 100644 --- 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_np *, struct iscsi_conn *); 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 *); diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 8c02fa34716f..f9cde9141836 100644 --- 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(struct iscsi_conn *conn, struct iscsi_log 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(struct iscsi_conn *conn, struct iscsi_log 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) diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h index 34117b8b72e4..0aedbb2c10e0 100644 --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -595,6 +595,7 @@ 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 */ -- 2.34.1