Commit c6ef8954 authored May 02, 2018 by Xiang Chen Committed by Martin K. Petersen May 08, 2018

scsi: hisi_sas: check sas_dev gone earlier in hisi_sas_abort_task()



It is possible to dereference a NULL-pointer in hisi_sas_abort_task() in
special scenario when the device has been removed.

If an SMP task times-out, it will call hisi_sas_abort_task() to
recover. And currently there is a check in hisi_sas_abort_task() to
avoid the situation of processing the abort for the removed device.

However we have an ordering problem, in that we may reference a task for
the removed device before checking if the device has been removed.

Fix this by only referencing the sas_dev after we know it is still
present.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent a14da7a2

drivers/scsi/hisi_sas/hisi_sas_main.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -1166,15 +1166,16 @@ static int hisi_sas_abort_task(struct sas_task *task)
		struct hisi_sas_tmf_task tmf_task;
		struct domain_device *device = task->dev;
		struct hisi_sas_device *sas_dev = device->lldd_dev;
		struct hisi_hba *hisi_hba = dev_to_hisi_hba(task->dev);
		struct device *dev = hisi_hba->dev;
		struct hisi_hba *hisi_hba;
		struct device *dev;
		int rc = TMF_RESP_FUNC_FAILED;
		unsigned long flags;

		if (!sas_dev) {
		dev_warn(dev, "Device has been removed\n");
		if (!sas_dev)
		return TMF_RESP_FUNC_FAILED;
		}

		hisi_hba = dev_to_hisi_hba(task->dev);
		dev = hisi_hba->dev;

		spin_lock_irqsave(&task->task_state_lock, flags);
		if (task->task_state_flags & SAS_TASK_STATE_DONE) {