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iscsi-target: Fix iscsit_start_kthreads failure OOPs

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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 88dcd2dab5
    Author: Nicholas Bellinger <nab@linux-iscsi.org>
    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 <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2015-07-22 23:14:19 -07:00
parent 417c20a9bd
commit e54198657b
5 changed files with 68 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/target/iscsi/iscsi_target.c
View File

@ -3998,6 +3998,12 @@ get_immediate:
}
transport_err:
/*
* 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);

45
drivers/target/iscsi/iscsi_target_login.c
View File

@ -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);
}

3
drivers/target/iscsi/iscsi_target_login.h
View File

@ -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 *);

34
drivers/target/iscsi/iscsi_target_nego.c
View File

@ -17,6 +17,7 @@
******************************************************************************/
#include <linux/ctype.h>
#include <linux/kthread.h>
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
@ -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)

1
include/target/iscsi/iscsi_target_core.h
View File

@ -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 */