Patch "iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
iscsi-target-fix-early-sk_data_ready-login_flags_ready-race.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Nicholas Bellinger <[email protected]>
Date: Sat, 27 Feb 2016 18:15:46 -0800
Subject: iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race

From: Nicholas Bellinger <[email protected]>

commit 8f0dfb3d8b1120c61f6e2cc3729290db10772b2d upstream.

There is a iscsi-target/tcp login race in LOGIN_FLAGS_READY state assignment that can result in frequent errors during iscsi discovery:

"iSCSI Login negotiation failed."

To address this bug, move the initial LOGIN_FLAGS_READY assignment ahead of iscsi_target_do_login() when handling the initial iscsi_target_start_negotiation() request PDU during connection login.

As iscsi_target_do_login_rx() work_struct callback is clearing LOGIN_FLAGS_READ_ACTIVE after subsequent calls to iscsi_target_do_login(), the early sk_data_ready ahead of the first iscsi_target_do_login() expects LOGIN_FLAGS_READY to also be set for the initial login request PDU.

As reported by Maged, this was first obsered using an MSFT initiator running across multiple VMWare host virtual machines with iscsi-target/tcp.

---
 drivers/target/iscsi/iscsi_target_nego.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

@@ -1251,16 +1251,16 @@ int iscsi_target_start_negotiation(
 {
 	int ret;
 
-	ret = iscsi_target_do_login(conn, login);
-	if (!ret) {
-		if (conn->sock) {
-			struct sock *sk = conn->sock->sk;
+       if (conn->sock) {
+               struct sock *sk = conn->sock->sk;
 
-			write_lock_bh(&sk->sk_callback_lock);
-			set_bit(LOGIN_FLAGS_READY, &conn->login_flags);
-			write_unlock_bh(&sk->sk_callback_lock);
-		}
-	} else if (ret < 0) {
+               write_lock_bh(&sk->sk_callback_lock);
+               set_bit(LOGIN_FLAGS_READY, &conn->login_flags);
+               write_unlock_bh(&sk->sk_callback_lock);
+       }
+
+       ret = iscsi_target_do_login(conn, login);
+       if (ret < 0) {
 		cancel_delayed_work_sync(&conn->login_work);
 		cancel_delayed_work_sync(&conn->login_cleanup_work);
 		iscsi_target_restore_sock_callbacks(conn);

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/iscsi-target-fix-delayed-logout-processing-greater-than-seconds_for_logout_comp.patch queue-3.18/iscsi-target-always-wait-for-kthread_should_stop-before-kthread-exit.patch queue-3.18/iscsi-target-fix-early-sk_data_ready-login_flags_ready-race.patch queue-3.18/iscsi-target-fix-initial-login-pdu-asynchronous-socket-close-oops.patch queue-3.18/target-avoid-mappedlun-symlink-creation-during-lun-shutdown.patch