Patch "target: Fix caw_sem leak in transport_generic_request_failure" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

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

    target: Fix caw_sem leak in transport_generic_request_failure

to the 4.14-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:
     target-fix-caw_sem-leak-in-transport_generic_request_failure.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From fd2f928b0ddd2fe8876d4f1344df2ace2b715a4d Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Fri, 29 Sep 2017 16:03:24 -0700
Subject: target: Fix caw_sem leak in transport_generic_request_failure

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit fd2f928b0ddd2fe8876d4f1344df2ace2b715a4d upstream.

With the recent addition of transport_check_aborted_status() within
transport_generic_request_failure() to avoid sending a SCSI status
exception after CMD_T_ABORTED w/ TAS=1 has occured, it introduced
a COMPARE_AND_WRITE early failure regression.

Namely when COMPARE_AND_WRITE fails and se_device->caw_sem has
been taken by sbc_compare_and_write(), if the new check for
transport_check_aborted_status() returns true and exits,
cmd->transport_complete_callback() -> compare_and_write_post()
is skipped never releasing se_device->caw_sem.

This regression was originally introduced by:

  commit e3b88ee95b4e4bf3e9729a4695d695b9c7c296c8
  Author: Bart Van Assche <bart.vanassche@sandisk.com>
  Date:   Tue Feb 14 16:25:45 2017 -0800

      target: Fix handling of aborted failed commands

To address this bug, move the transport_check_aborted_status()
call after transport_complete_task_attr() and
cmd->transport_complete_callback().

Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/target/target_core_transport.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1730,9 +1730,6 @@ void transport_generic_request_failure(s
 {
 	int ret = 0, post_ret = 0;
 
-	if (transport_check_aborted_status(cmd, 1))
-		return;
-
 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
 		 sense_reason);
 	target_show_cmd("-----[ ", cmd);
@@ -1741,6 +1738,7 @@ void transport_generic_request_failure(s
 	 * For SAM Task Attribute emulation for failed struct se_cmd
 	 */
 	transport_complete_task_attr(cmd);
+
 	/*
 	 * Handle special case for COMPARE_AND_WRITE failure, where the
 	 * callback is expected to drop the per device ->caw_sem.
@@ -1749,6 +1747,9 @@ void transport_generic_request_failure(s
 	     cmd->transport_complete_callback)
 		cmd->transport_complete_callback(cmd, false, &post_ret);
 
+	if (transport_check_aborted_status(cmd, 1))
+		return;
+
 	switch (sense_reason) {
 	case TCM_NON_EXISTENT_LUN:
 	case TCM_UNSUPPORTED_SCSI_OPCODE:


Patches currently in stable-queue which might be from nab@linux-iscsi.org are

queue-4.14/target-fix-null-pointer-regression-in-core_tmr_drain_tmr_list.patch
queue-4.14/iscsi-target-make-task_reassign-use-proper-se_cmd-cmd_kref.patch
queue-4.14/target-fix-queue_full-scsi-task-attribute-handling.patch
queue-4.14/target-fix-buffer-offset-in-core_scsi3_pri_read_full_status.patch
queue-4.14/iscsi-target-fix-non-immediate-tmr-reference-leak.patch
queue-4.14/target-fix-caw_sem-leak-in-transport_generic_request_failure.patch
queue-4.14/target-avoid-early-cmd_t_pre_execute-failures-during-abort_task.patch
queue-4.14/target-fix-quiese-during-transport_write_pending_qf-endless-loop.patch