diff options
authorNicholas Bellinger <nab@linux-iscsi.org>2013-10-01 16:53:10 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2013-10-03 04:24:06 -0700
commitd8855c154e748c9ccd7c78e6478560ed61438e7d (patch)
parentb7191253b302a9b98758c3616761ae111b6264b9 (diff)
target: Fix recursive COMPARE_AND_WRITE callback failure
This patch addresses a bug when compare_and_write_callback() invoked from target_complete_ok_work() hits an failure from __target_execute_cmd() -> cmd->execute_cmd(), that ends up calling transport_generic_request_failure() -> compare_and_write_post(), thus causing SCF_COMPARE_AND_WRITE_POST to incorrectly be set. The result of this bug is that target_complete_ok_work() no longer hits the if (!rc && !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST) check that forces an immediate return, and instead double completes the se_cmd in question, triggering an OOPs in the process. This patch changes compare_and_write_post() to only set this bit when a failure has not already occured to ensure the immediate return from within target_complete_ok_work(), and thus allow transport_generic_request_failure() to handle the sending of the CHECK_CONDITION exception status. Reported-by: Thomas Glanzmann <thomas@glanzmann.de> Tested-by: Thomas Glanzmann <thomas@glanzmann.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index a9dca116011e..1393d0ed746a 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -349,7 +349,16 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd)
struct se_device *dev = cmd->se_dev;
- cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
+ /*
+ * Only set SCF_COMPARE_AND_WRITE_POST to force a response fall-through
+ * within target_complete_ok_work() if the command was successfully
+ * sent to the backend driver.
+ */
+ spin_lock_irq(&cmd->t_state_lock);
+ if ((cmd->transport_state & CMD_T_SENT) && !cmd->scsi_status)
+ cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
+ spin_unlock_irq(&cmd->t_state_lock);
* Unlock ->caw_sem originally obtained during sbc_compare_and_write()
* before the original READ I/O submission.