[Devel] [PATCH RHEL7 COMMIT] ms/target: Drop incorrect ABORT_TASK put for completed commands

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.46.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.46.2
------>
commit 4e6e822b3f606f534eaa841511a2c055e89c32a0
Author: Nicholas Bellinger <nab at linux-iscsi.org>
Date:   Mon Apr 2 17:28:29 2018 +0300

    ms/target: Drop incorrect ABORT_TASK put for completed commands
    
    ML: 7f54ab5ff52fb0b91569bc69c4a6bc5cac1b768d
    
    This patch fixes a recent ABORT_TASK regression associated
    with commit febe562c, where a left-over target_put_sess_cmd()
    would still be called when __target_check_io_state() detected
    a command has already been completed, and explicit ABORT must
    be avoided.
    
    Note commit febe562c dropped the local kref_get_unless_zero()
    check in core_tmr_abort_task(), but did not drop this extra
    corresponding target_put_sess_cmd() in the failure path.
    
    So go ahead and drop this now bogus target_put_sess_cmd(),
    and avoid this potential use-after-free.
    
    Reported-by: Dan Lane <dracodan at gmail.com>
    Cc: Quinn Tran <quinn.tran at qlogic.com>
    Cc: Himanshu Madhani <himanshu.madhani at qlogic.com>
    Cc: Sagi Grimberg <sagig at mellanox.com>
    Cc: Christoph Hellwig <hch at lst.de>
    Cc: Hannes Reinecke <hare at suse.de>
    Cc: Andy Grover <agrover at redhat.com>
    Cc: Mike Christie <mchristi at redhat.com>
    Cc: stable at vger.kernel.org # 3.14+
    Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
    Signed-off-by: Andrei Vagin <avagin at openvz.org>
---
 drivers/target/target_core_tmr.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 956de70539c4..78562d93d02b 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -181,7 +181,6 @@ void core_tmr_abort_task(
 
 		if (!__target_check_io_state(se_cmd, se_sess, 0)) {
 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
-			target_put_sess_cmd(se_cmd);
 			goto out;
 		}
 		list_del_init(&se_cmd->se_cmd_list);