4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit 9b2792c3da1e80f2d460167d319302a24c9ca2b7 upstream.
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@xxxxxxxxx>
Cc: Donald White <dew@xxxxxxxxx>
Tested-by: Gary Guo <ghg@xxxxxxxxx>
Cc: Gary Guo <ghg@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/target/target_core_sbc.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -442,6 +442,7 @@ static sense_reason_t compare_and_write_
int *post_ret)
{
struct se_device *dev = cmd->se_dev;
+ sense_reason_t ret = TCM_NO_SENSE;
/*
* Only set SCF_COMPARE_AND_WRITE_POST to force a response fall-through
@@ -449,9 +450,12 @@ static sense_reason_t compare_and_write_
* sent to the backend driver.
*/
spin_lock_irq(&cmd->t_state_lock);
- if ((cmd->transport_state & CMD_T_SENT) && !cmd->scsi_status) {
+ if (cmd->transport_state & CMD_T_SENT) {
cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
*post_ret = 1;
+
+ if (cmd->scsi_status == SAM_STAT_CHECK_CONDITION)
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
spin_unlock_irq(&cmd->t_state_lock);
@@ -461,7 +465,7 @@ static sense_reason_t compare_and_write_
*/
up(&dev->caw_sem);
- return TCM_NO_SENSE;
+ return ret;
}
static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool success,
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html