From: Xiang Chen <chenxiang66@hisilicon.com>
Date: Wed, 2 May 2018 23:56:28 +0800
Subject: scsi: hisi_sas: check sas_dev gone earlier in hisi_sas_abort_task()
Git-commit: c6ef895472696cac8e50f0ce69b301cc10233a67
Patch-mainline: v4.18-rc1
References: FATE#326253
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>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
drivers/scsi/hisi_sas/hisi_sas_main.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 8f8e6424ee1d..24416bb66027 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -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) {