[PATCH] scsi_transport_sas: Potential NULL pointer deference in sas_rphy_match()

[Yizhuo]

Inside function sas_rphy_match(), dev_to_shost() could return NULL,
however, the return value of dev_to_shost() is not checked and
get used. This could potentially be unsafe.

Signed-off-by: Yizhuo <yzhai...@ucr.edu>
---
 drivers/scsi/scsi_transport_sas.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/scsi_transport_sas.c 
b/drivers/scsi/scsi_transport_sas.c
index ef138c57e2a6..04d83cbc35f2 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1328,6 +1328,8 @@ static int sas_rphy_match(struct attribute_container 
*cont, struct device *dev)
        if (!scsi_is_sas_rphy(dev))
                return 0;
        shost = dev_to_shost(dev->parent->parent);
+       if (!shost)
+               return 0;
 
        if (!shost->transportt)
                return 0;
-- 
2.17.1