From: Nicholas Bellinger <[email protected]> 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 <[email protected]> Cc: Thomas Glanzmann <[email protected]> Signed-off-by: Nicholas Bellinger <[email protected]> --- drivers/target/target_core_sbc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index a9dca11..1393d0e 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. -- 1.8.4.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
