target: Fix queue full status NULL pointer for SCF_TRANSPORT_TASK_SENSE

During temporary resource starvation at lower transport layer, command
is placed on queue full retry path, which expose this problem.  The TCM
queue full handling of SCF_TRANSPORT_TASK_SENSE currently sends the same
cmd twice to lower layer.  The 1st time led to cmd normal free path.
The 2nd time cause Null pointer access.

This regression bug was originally introduced v3.1-rc code in the
following commit:

commit e057f53308
Author: Christoph Hellwig <hch@infradead.org>
Date:   Mon Oct 17 13:56:41 2011 -0400

    target: remove the transport_qf_callback se_cmd callback

Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Cc: <stable@vger.kernel.org> # v3.1+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Quinn Tran 2014-09-25 06:22:28 -04:00 committed by Nicholas Bellinger
parent db3a99b992
commit 082f58ac4a

View file

@ -1871,8 +1871,7 @@ static void transport_complete_qf(struct se_cmd *cmd)
if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
trace_target_cmd_complete(cmd);
ret = cmd->se_tfo->queue_status(cmd);
if (ret)
goto out;
goto out;
}
switch (cmd->data_direction) {