On 2018-08-02 11:33, Marc Kleine-Budde wrote:
Adding Jimmy's other email on Cc.
Thanks Marc!
On 08/02/2018 11:02 AM, Dan Carpenter wrote:
Hello Jimmy Assarsson,
The patch aec5fb2268b7: "can: kvaser_usb: Add support for Kvaser USB
hydra family" from Jul 18, 2018, leads to the following static
checker warning:
drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c:1035 kvaser_usb_hydra_error_frame()
error: potentially dereferencing uninitialized 'cf'.
Hi Dan,
Thanks for finding this! Which flags should I pass to smatch, in order
to find this error, and also the "freed memory" bug you reported here
https://marc.info/?l=linux-can&m=153312263609557
Didn't find any errors when running:
$ /xx/smatch/smatch_scripts/kchecker drivers/net/can/usb/kvaser_usb/
Best Regards,
jimmy
drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
1010 skb = alloc_can_err_skb(netdev, &cf);
^^^
Assume this fails and skb is NULL.
1011
1012 if (new_state != old_state) {
1013 if (skb) {
^^^
1014 enum can_state tx_state, rx_state;
1015
1016 tx_state = (bec.txerr >= bec.rxerr) ?
1017 new_state : CAN_STATE_ERROR_ACTIVE;
1018 rx_state = (bec.txerr <= bec.rxerr) ?
1019 new_state : CAN_STATE_ERROR_ACTIVE;
1020
1021 can_change_state(netdev, cf, tx_state, rx_state);
1022 }
1023
1024 if (new_state == CAN_STATE_BUS_OFF) {
1025 if (!priv->can.restart_ms)
1026 kvaser_usb_hydra_send_simple_cmd_async
1027 (priv, CMD_STOP_CHIP_REQ);
1028
1029 can_bus_off(netdev);
1030 }
1031
1032 if (priv->can.restart_ms &&
1033 old_state >= CAN_STATE_BUS_OFF &&
1034 new_state < CAN_STATE_BUS_OFF)
1035 cf->can_id |= CAN_ERR_RESTARTED;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Potentially uninitialized
1036 }
1037
1038 if (!skb) {
^^^^^
1039 stats->rx_dropped++;
1040 netdev_warn(netdev, "No memory left for err_skb\n");
1041 return;
1042 }
regards,
dan carpenter
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