| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 037/144] iscsi-target: Fix incorrect np->np_thread NULL assignment | Date | Mon, 6 Jan 2014 14:36:38 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Nicholas Bellinger <nab@linux-iscsi.org>
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@suse.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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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