[PATCH 3.11 071/144] sfc: check for NULL efx->ptp_data in efx_ptp_event

[Luis Henriques]

3.11.10.7 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Edward Cree <ecree at solarflare.com>

commit 8f355e5cee63c2c0c145d8206c4245d0189f47ff upstream.

If we receive a PTP event from the NIC when we haven't set up PTP state
in the driver, we attempt to read through a NULL pointer efx->ptp_data,
triggering a panic.

Signed-off-by: Edward Cree <ecree at solarflare.com>
Acked-by: Shradha Shah <sshah at solarflare.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/sfc/ptp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 11d979d..d77016f 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -1353,6 +1353,13 @@ void efx_ptp_event(struct efx_nic *efx, efx_qword_t *ev)
 	struct efx_ptp_data *ptp = efx->ptp_data;
 	int code = EFX_QWORD_FIELD(*ev, MCDI_EVENT_CODE);
 
+	if (!ptp) {
+		if (net_ratelimit())
+			netif_warn(efx, drv, efx->net_dev,
+				   "Received PTP event but PTP not set up\n");
+		return;
+	}
+
 	if (!ptp->enabled)
 		return;
 
-- 
1.9.1