[PATCH 4.2.y-ckt 70/98] target: Drop incorrect ABORT_TASK put for completed commands

Kamal Mostafa
2016-03-15T23:33:16Z

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

commit 7f54ab5ff52fb0b91569bc69c4a6bc5cac1b768d upstream.

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@gmail.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
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 88029cc..46b1991 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -177,7 +177,6 @@ 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);
--
2.7.0