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can: gs_usb: gs_can_open(): fix race dev->can.state condition

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The dev->can.state is set to CAN_STATE_ERROR_ACTIVE, after the device
has been started. On busy networks the CAN controller might receive
CAN frame between and go into an error state before the dev->can.state
is assigned.

Assign dev->can.state before starting the controller to close the race
window.

Fixes: d08e973a77 ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://lore.kernel.org/all/20220920195216.232481-1-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2022-09-20 11:40:56 +02:00
parent a09721dd47
commit 5440428b3d
1 changed files with 2 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/net/can/usb/gs_usb.c
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@ -824,6 +824,7 @@ static int gs_can_open(struct net_device *netdev)
flags |= GS_CAN_MODE_TRIPLE_SAMPLE; flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
/* finally start device */ /* finally start device */
dev->can.state = CAN_STATE_ERROR_ACTIVE;
dm->mode = cpu_to_le32(GS_CAN_MODE_START); dm->mode = cpu_to_le32(GS_CAN_MODE_START);
dm->flags = cpu_to_le32(flags); dm->flags = cpu_to_le32(flags);
rc = usb_control_msg(interface_to_usbdev(dev->iface), rc = usb_control_msg(interface_to_usbdev(dev->iface),
@ -835,13 +836,12 @@ static int gs_can_open(struct net_device *netdev)
if (rc < 0) { if (rc < 0) {
netdev_err(netdev, "Couldn't start device (err=%d)\n", rc); netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
kfree(dm); kfree(dm);
dev->can.state = CAN_STATE_STOPPED;
return rc; return rc;
} }
kfree(dm); kfree(dm);
dev->can.state = CAN_STATE_ERROR_ACTIVE;
parent->active_channels++; parent->active_channels++;
if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)) if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
netif_start_queue(netdev); netif_start_queue(netdev);