Hello John Garry,
The patch dc8a49cabc73: "scsi: hisi_sas: add internal abort to
hisi_sas_abort_task()" from Aug 24, 2016, leads to the following
static checker warning:
drivers/scsi/hisi_sas/hisi_sas_main.c:848 hisi_sas_abort_task()
error: we previously assumed 'slot' could be null (see line 847)
drivers/scsi/hisi_sas/hisi_sas_main.c
809 spin_unlock_irqrestore(&task->task_state_lock, flags);
810 sas_dev->dev_status = HISI_SAS_DEV_EH;
811 if (task->lldd_task && task->task_proto & SAS_PROTOCOL_SSP) {
^^^^^^^^^^^^^^^
We assume that ->lldd_task can be NULL.
812 struct scsi_cmnd *cmnd = task->uldd_task;
813 struct hisi_sas_slot *slot = task->lldd_task;
814 u32 tag = slot->idx;
815
816 int_to_scsilun(cmnd->device->lun, &lun);
817 tmf_task.tmf = TMF_ABORT_TASK;
818 tmf_task.tag_of_task_to_be_managed = cpu_to_le16(tag);
819
820 rc = hisi_sas_debug_issue_ssp_tmf(task->dev, lun.scsi_lun,
821 &tmf_task);
822
823 /* if successful, clear the task and callback forwards.*/
824 if (rc == TMF_RESP_FUNC_COMPLETE) {
825 if (task->lldd_task) {
826 struct hisi_sas_slot *slot;
827
828 slot = &hisi_hba->slot_info
829 [tmf_task.tag_of_task_to_be_managed];
830 spin_lock_irqsave(&hisi_hba->lock, flags);
831 hisi_hba->hw->slot_complete(hisi_hba, slot, 1);
832 spin_unlock_irqrestore(&hisi_hba->lock, flags);
833 }
834 }
835
836 hisi_sas_internal_task_abort(hisi_hba, device,
837 HISI_SAS_INT_ABT_CMD, tag);
838 } else if (task->task_proto & SAS_PROTOCOL_SATA ||
839 task->task_proto & SAS_PROTOCOL_STP) {
840 if (task->dev->dev_type == SAS_SATA_DEV) {
841 hisi_sas_internal_task_abort(hisi_hba, device,
842 HISI_SAS_INT_ABT_DEV, 0);
843 rc = TMF_RESP_FUNC_COMPLETE;
844 }
845 } else if (task->task_proto & SAS_PROTOCOL_SMP) {
846 /* SMP */
847 struct hisi_sas_slot *slot = task->lldd_task;
We assign it to slot.
848 u32 tag = slot->idx;
^^^^^^^^^
slot dereferenced without checking.
849
850 hisi_sas_internal_task_abort(hisi_hba, device,
851 HISI_SAS_INT_ABT_CMD, tag);
852 }
regards,
dan carpenter
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