From: Marc Kleine-Budde Date: Tue, 20 Sep 2022 09:46:12 +0000 (+0200) Subject: can: gs_usb: gs_can_open(): initialize time counter before starting device X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=103108cb9673814a1f73522dacc79ad28cfc0271;p=linux.git can: gs_usb: gs_can_open(): initialize time counter before starting device On busy networks the CAN controller might receive CAN frames directly after starting it but before the timecounter is setup. This will lead to NULL pointer deref while converting the converting the CAN frame's timestamp with the timecounter. Close the race window by setting up the timecounter before starting the CAN controller. Fixes: 45dfa45f52e6 ("can: gs_usb: add RX and TX hardware timestamp support") Link: https://lore.kernel.org/all/20220921081329.385509-1-mkl@pengutronix.de Cc: John Whittington Signed-off-by: Marc Kleine-Budde --- diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index 9a8a7f1b20021..aa619dfc3ff2a 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -972,6 +972,10 @@ static int gs_can_open(struct net_device *netdev) if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) flags |= GS_CAN_MODE_HW_TIMESTAMP; + /* start polling timestamp */ + if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) + gs_usb_timestamp_init(dev); + /* finally start device */ dev->can.state = CAN_STATE_ERROR_ACTIVE; dm->mode = cpu_to_le32(GS_CAN_MODE_START); @@ -985,16 +989,14 @@ static int gs_can_open(struct net_device *netdev) if (rc < 0) { netdev_err(netdev, "Couldn't start device (err=%d)\n", rc); kfree(dm); + if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) + gs_usb_timestamp_stop(dev); dev->can.state = CAN_STATE_STOPPED; return rc; } kfree(dm); - /* start polling timestamp */ - if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) - gs_usb_timestamp_init(dev); - parent->active_channels++; if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)) netif_start_queue(netdev);