[PATCH AUTOSEL 4.19 058/172] scsi: qedf: Fix crash when MFW calls for protocol stats while function is still probing

Sasha Levin
2020-06-18T01:27:01Z

From: Chad Dupuis <cdupuis@marvell.com>

[ Upstream commit ad40f5256095c68dc17c991eb976261d5ea2daaa ]

The MFW may make a call to qed and then to qedf for protocol statistics
while the function is still probing. If this happens it's possible that
some members of the struct qedf_ctx may not be fully initialized which can
result in a NULL pointer dereference or general protection fault.

To prevent this, add a new flag call QEDF_PROBING and set it when the
__qedf_probe() function is active. Then in the qedf_get_protocol_tlv_data()
function we can check if the function is still probing and return
immediantely before any uninitialized structures can be touched.

Link: https://lore.kernel.org/r/20200416084314.18851-9-skashyap@marvell.com
Signed-off-by: Chad Dupuis <cdupuis@marvell.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qedf/qedf.h | 1 +
drivers/scsi/qedf/qedf_main.c | 35 +++++++++++++++++++++++++++++++----
2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/qedf/qedf.h b/drivers/scsi/qedf/qedf.h
index 2c78d8fb9122..fc06be4fd10c 100644
--- a/drivers/scsi/qedf/qedf.h
+++ b/drivers/scsi/qedf/qedf.h
@@ -335,6 +335,7 @@ struct qedf_ctx {
#define QEDF_GRCDUMP_CAPTURE 4
#define QEDF_IN_RECOVERY 5
#define QEDF_DBG_STOP_IO 6
+#define QEDF_PROBING 8
unsigned long flags; /* Miscellaneous state flags */
int fipvlan_retries;
u8 num_queues;
diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
index cd61905ca2f5..b253523217b8 100644
--- a/drivers/scsi/qedf/qedf_main.c
+++ b/drivers/scsi/qedf/qedf_main.c
@@ -2961,7 +2961,7 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
{
int rc = -EINVAL;
struct fc_lport *lport;
- struct qedf_ctx *qedf;
+ struct qedf_ctx *qedf = NULL;
struct Scsi_Host *host;
bool is_vf = false;
struct qed_ll2_params params;
@@ -2989,6 +2989,7 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)

/* Initialize qedf_ctx */
qedf = lport_priv(lport);
+ set_bit(QEDF_PROBING, &qedf->flags);
qedf->lport = lport;
qedf->ctlr.lp = lport;
qedf->pdev = pdev;
@@ -3011,9 +3012,12 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
} else {
/* Init pointers during recovery */
qedf = pci_get_drvdata(pdev);
+ set_bit(QEDF_PROBING, &qedf->flags);
lport = qedf->lport;
}

+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_DISC, "Probe started.\n");
+
host = lport->host;

/* Allocate mempool for qedf_io_work structs */
@@ -3312,6 +3316,10 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
else
fc_fabric_login(lport);

+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_DISC, "Probe done.\n");
+
+ clear_bit(QEDF_PROBING, &qedf->flags);
+
/* All good */
return 0;

@@ -3337,6 +3345,11 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
err1:
scsi_host_put(lport->host);
err0:
+ if (qedf) {
+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_DISC, "Probe done.\n");
+
+ clear_bit(QEDF_PROBING, &qedf->flags);
+ }
return rc;
}

@@ -3484,11 +3497,25 @@ void qedf_get_protocol_tlv_data(void *dev, void *data)
{
struct qedf_ctx *qedf = dev;
struct qed_mfw_tlv_fcoe *fcoe = data;
- struct fc_lport *lport = qedf->lport;
- struct Scsi_Host *host = lport->host;
- struct fc_host_attrs *fc_host = shost_to_fc_host(host);
+ struct fc_lport *lport;
+ struct Scsi_Host *host;
+ struct fc_host_attrs *fc_host;
struct fc_host_statistics *hst;

+ if (!qedf) {
+ QEDF_ERR(NULL, "qedf is null.\n");
+ return;
+ }
+
+ if (test_bit(QEDF_PROBING, &qedf->flags)) {
+ QEDF_ERR(&qedf->dbg_ctx, "Function is still probing.\n");
+ return;
+ }
+
+ lport = qedf->lport;
+ host = lport->host;
+ fc_host = shost_to_fc_host(host);
+
/* Force a refresh of the fc_host stats including offload stats */
hst = qedf_fc_get_host_stats(host);

--
2.25.1