3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit db6077fd0b7dd41dc6ff18329cec979379071f87 upstream.
When shutting down a target there is a race condition between
iscsit_del_np() and __iscsi_target_login_thread().
The latter sets the thread pointer to NULL, and the former
tries to issue kthread_stop() on that pointer without any
synchronization.
This patch moves the np->np_thread NULL assignment into
iscsit_del_np(), after kthread_stop() has completed. It also
removes the signal_pending() + np_state check, and only
exits when kthread_should_stop() is true.
Reported-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target.c | 1 +
drivers/target/iscsi/iscsi_target_login.c | 6 ------
2 files changed, 1 insertion(+), 6 deletions(-)
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -465,6 +465,7 @@ int iscsit_del_np(struct iscsi_np *np)
*/
send_sig(SIGINT, np->np_thread, 1);
kthread_stop(np->np_thread);
+ np->np_thread = NULL;
}
np->np_transport->iscsit_free_np(np);
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -1404,11 +1404,6 @@ old_sess_out:
out:
stop = kthread_should_stop();
- if (!stop && signal_pending(current)) {
- spin_lock_bh(&np->np_thread_lock);
- stop = (np->np_thread_state == ISCSI_NP_THREAD_SHUTDOWN);
- spin_unlock_bh(&np->np_thread_lock);
- }
/* Wait for another socket.. */
if (!stop)
return 1;
@@ -1416,7 +1411,6 @@ exit:
iscsi_stop_login_thread_timer(np);
spin_lock_bh(&np->np_thread_lock);
np->np_thread_state = ISCSI_NP_THREAD_EXIT;
- np->np_thread = NULL;
spin_unlock_bh(&np->np_thread_lock);
return 0;
--
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