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 patchs adds proper synchronization pointer between those calls to ensure that a) the thread is correctly terminate and b) kthread_stop() isn't called with a NULL pointer. In the long run iscsi_target_login_thread() should be converted into a workqueue. Signed-off-by: Hannes Reinecke <[email protected]> --- drivers/target/iscsi/iscsi_target.c | 12 +++++++++--- drivers/target/iscsi/iscsi_target_login.c | 9 ++++++--- 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index bf76fc4..c7bf3c9 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -457,15 +457,21 @@ int iscsit_del_np(struct iscsi_np *np) } np->np_thread_state = ISCSI_NP_THREAD_SHUTDOWN; spin_unlock_bh(&np->np_thread_lock); - - if (np->np_thread) { + /* Give __iscsi_target_login_thread() a chance to run */ + schedule(); + spin_lock_bh(&np->np_thread_lock); + if ((np->np_thread_state == ISCSI_NP_THREAD_SHUTDOWN) + && np->np_thread) { + np->np_thread_state = ISCSI_NP_THREAD_EXIT; + spin_unlock_bh(&np->np_thread_lock); /* * We need to send the signal to wakeup Linux/Net * which may be sleeping in sock_accept().. */ send_sig(SIGINT, np->np_thread, 1); kthread_stop(np->np_thread); - } + } else + spin_unlock_bh(&np->np_thread_lock); np->np_transport->iscsit_free_np(np); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index 4eb93b2..b375d26 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -1405,7 +1405,8 @@ 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); + stop = (np->np_thread_state == ISCSI_NP_THREAD_SHUTDOWN || + np->np_thread_state == ISCSI_NP_THREAD_EXIT); spin_unlock_bh(&np->np_thread_lock); } /* Wait for another socket.. */ @@ -1414,8 +1415,10 @@ out: 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; + if (np->np_thread_state != ISCSI_NP_THREAD_EXIT) { + np->np_thread_state = ISCSI_NP_THREAD_EXIT; + np->np_thread = NULL; + } spin_unlock_bh(&np->np_thread_lock); return 0; -- 1.7.12.4 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
