Patch "iscsi-target: Fix iser explicit logout TX kthread leak" has been added to the 3.14-stable tree

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

iscsi-target: Fix iser explicit logout TX kthread leak

to the 3.14-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-iser-explicit-logout-tx-kthread-leak.patch
and it can be found in the queue-3.14 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: Thu, 23 Jul 2015 22:30:31 +0000
Subject: iscsi-target: Fix iser explicit logout TX kthread leak

From: Nicholas Bellinger <[email protected]>

commit 007d038bdf95ccfe2491d0078be54040d110fd06 upstream.

This patch fixes a regression introduced with the following commit in v4.0-rc1 code, where an explicit iser-target logout would result in ->tx_thread_active being incorrectly cleared by the logout post handler, and subsequent TX kthread leak:

commit 88dcd2dab5c23b1c9cfc396246d8f476c872f0ca
Author: Nicholas Bellinger <[email protected]>
Date: Thu Feb 26 22:19:15 2015 -0800

iscsi-target: Convert iscsi_thread_set usage to kthread.h

To address this bug, change iscsit_logout_post_handler_closesession() and iscsit_logout_post_handler_samecid() to only cmpxchg() on ->tx_thread_active for traditional iscsi/tcp connections.

This is required because iscsi/tcp connections are invoking logout post handler logic directly from TX kthread context, while iser connections are invoking logout post handler logic from a seperate workqueue context.

---
 drivers/target/iscsi/iscsi_target.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

@@ -4476,7 +4476,18 @@ static void iscsit_logout_post_handler_c
 	struct iscsi_conn *conn)
 {
 	struct iscsi_session *sess = conn->sess;
-	int sleep = cmpxchg(&conn->tx_thread_active, true, false);
+	int sleep = 1;
+	/*
+	 * Traditional iscsi/tcp will invoke this logic from TX thread
+	 * context during session logout, so clear tx_thread_active and
+	 * sleep if iscsit_close_connection() has not already occured.
+	 *
+	 * Since iser-target invokes this logic from it's own workqueue,
+	 * always sleep waiting for RX/TX thread shutdown to complete
+	 * within iscsit_close_connection().
+	 */
+	if (conn->conn_transport->transport_type == ISCSI_TCP)
+		sleep = cmpxchg(&conn->tx_thread_active, true, false);
 
 	atomic_set(&conn->conn_logout_remove, 0);
 	complete(&conn->conn_logout_comp);

@@ -4490,7 +4501,10 @@ static void iscsit_logout_post_handler_c
 static void iscsit_logout_post_handler_samecid(
 	struct iscsi_conn *conn)
 {
-	int sleep = cmpxchg(&conn->tx_thread_active, true, false);
+	int sleep = 1;
+
+	if (conn->conn_transport->transport_type == ISCSI_TCP)
+		sleep = cmpxchg(&conn->tx_thread_active, true, false);
 
 	atomic_set(&conn->conn_logout_remove, 0);
 	complete(&conn->conn_logout_comp);

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

queue-3.14/iscsi-target-fix-iser-explicit-logout-tx-kthread-leak.patch queue-3.14/iscsi-target-fix-use-after-free-during-tpg-session-shutdown.patch