target: Fix COMPARE_AND_WRITE ref leak for non GOOD status
authorNicholas Bellinger <nab@linux-iscsi.org>
Mon, 6 Feb 2017 22:28:09 +0000 (14:28 -0800)
committerNicholas Bellinger <nab@linux-iscsi.org>
Wed, 8 Feb 2017 16:25:39 +0000 (08:25 -0800)
commit9b2792c3da1e80f2d460167d319302a24c9ca2b7
treebb4d91a9afef948324092f9d4190773de79b8d5d
parent01d4d673558985d9a118e1e05026633c3e2ade9b
target: Fix COMPARE_AND_WRITE ref leak for non GOOD status

This patch addresses a long standing bug where the commit phase
of COMPARE_AND_WRITE would result in a se_cmd->cmd_kref reference
leak if se_cmd->scsi_status returned non SAM_STAT_GOOD.

This would manifest first as a lost SCSI response, and eventual
hung task during fabric driver logout or re-login, as existing
shutdown logic waited for the COMPARE_AND_WRITE se_cmd->cmd_kref
to reach zero.

To address this bug, compare_and_write_post() has been changed
to drop the incorrect !cmd->scsi_status conditional that was
preventing *post_ret = 1 for being set during non SAM_STAT_GOOD
status.

This patch has been tested with SAM_STAT_CHECK_CONDITION status
from normal target_complete_cmd() callback path, as well as the
incoming __target_execute_cmd() submission failure path when
se_cmd->execute_cmd() returns non zero status.

Reported-by: Donald White <dew@datera.io>
Cc: Donald White <dew@datera.io>
Tested-by: Gary Guo <ghg@datera.io>
Cc: Gary Guo <ghg@datera.io>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
drivers/target/target_core_sbc.c