diff options
author | Jiang Yi <jiangyilism@gmail.com> | 2017-05-16 17:57:55 +0800 |
---|---|---|
committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2017-05-31 15:12:57 -0700 |
commit | 5e0cf5e6c43b9e19fc0284f69e5cd2b4a47523b0 (patch) | |
tree | 7b1807ba795acf651f2599442806f7f96649daf1 /drivers/target/iscsi/iscsi_target.c | |
parent | 25cdda95fda78d22d44157da15aa7ea34be3c804 (diff) | |
download | linux-5e0cf5e6c43b9e19fc0284f69e5cd2b4a47523b0.tar.bz2 |
iscsi-target: Always wait for kthread_should_stop() before kthread exit
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 <jiangyilism@gmail.com>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/iscsi/iscsi_target.c')
-rw-r--r-- | drivers/target/iscsi/iscsi_target.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 26a9bcd5ee6a..0d8f81591bed 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -3790,6 +3790,8 @@ 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. @@ -3815,12 +3817,14 @@ 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: @@ -3830,8 +3834,13 @@ 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; } @@ -4004,6 +4013,7 @@ int iscsi_target_rx_thread(void *arg) { int rc; struct iscsi_conn *conn = arg; + bool conn_freed = false; /* * Allow ourselves to be interrupted by SIGINT so that a @@ -4016,7 +4026,7 @@ 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->iscsit_get_rx_pdu) return 0; @@ -4025,7 +4035,15 @@ int iscsi_target_rx_thread(void *arg) 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; } |