netdev - [PATCH net-next 2/2] ionic: prevent early watchdog check

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Date:   Tue, 29 Sep 2020 15:19:56 -0700
From:   Shannon Nelson <snelson@...sando.io>
To:     netdev@...r.kernel.org, davem@...emloft.net
Cc:     Shannon Nelson <snelson@...sando.io>
Subject: [PATCH net-next 2/2] ionic: prevent early watchdog check

In one corner case scenario, the driver device lif setup can
get delayed such that the ionic_watchdog_cb() timer goes off
before the ionic->lif is set, thus causing a NULL pointer panic.
We catch the problem by checking for a NULL lif just a little
earlier in the callback.

Signed-off-by: Shannon Nelson <snelson@...sando.io>
---
 drivers/net/ethernet/pensando/ionic/ionic_dev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.c b/drivers/net/ethernet/pensando/ionic/ionic_dev.c
index 306e9401b09b..f90322ec3e18 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.c
@@ -19,9 +19,12 @@ static void ionic_watchdog_cb(struct timer_list *t)
 	mod_timer(&ionic->watchdog_timer,
 		  round_jiffies(jiffies + ionic->watchdog_period));
 
+	if (!ionic->lif)
+		return;
+
 	hb = ionic_heartbeat_check(ionic);
 
-	if (hb >= 0 && ionic->lif)
+	if (hb >= 0)
 		ionic_link_status_check_request(ionic->lif);
 }
 
-- 
2.17.1