Function es58x_fd_rx_event() invokes the es58x_check_msg_len() macro: | ret = es58x_check_msg_len(es58x_dev->dev, *rx_event_msg, msg_len); While doing so, it deferences an uninitialized variable: *rx_event_msg. This is actually harmless because es58x_check_msg_len() only uses preprocessors macro (sizeof() and __stringify()) on *rx_event_msg. c.f. [1]. Nonetheless, this pattern is confusing so the lines are reordered to make sure that rx_event_msg is correctly initialized. This patch also fixes a false positive warning reported by cppcheck: | cppcheck possible warnings: (new ones prefixed by >>, may not be real problems) | | In file included from drivers/net/can/usb/etas_es58x/es58x_fd.c: | >> drivers/net/can/usb/etas_es58x/es58x_fd.c:174:8: warning: Uninitialized variable: rx_event_msg [uninitvar] | ret = es58x_check_msg_len(es58x_dev->dev, *rx_event_msg, msg_len); | ^ [1] https://elixir.bootlin.com/linux/latest/source/drivers/net/can/usb/etas_es58x/es58x_core.h#L467 Reported-by: kernel test robot <yujie.liu@xxxxxxxxx> Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> --- As discussed in https://lore.kernel.org/linux-can/20220302130423.ddd2ulldffpo5lb2@xxxxxxxxxxxxxx/T/#u, no need to backport this patch because this is not a fix. @Yujie Liu: I added the "Reported-by: kernel test robot". This being a false positive, let me know if you would like to remove the tag in order not to mess with you statistics. --- drivers/net/can/usb/etas_es58x/es58x_fd.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c index 88d2540abbbe..c97ffa71fd75 100644 --- a/drivers/net/can/usb/etas_es58x/es58x_fd.c +++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c @@ -173,12 +173,11 @@ static int es58x_fd_rx_event_msg(struct net_device *netdev, const struct es58x_fd_rx_event_msg *rx_event_msg; int ret; + rx_event_msg = &es58x_fd_urb_cmd->rx_event_msg; ret = es58x_check_msg_len(es58x_dev->dev, *rx_event_msg, msg_len); if (ret) return ret; - rx_event_msg = &es58x_fd_urb_cmd->rx_event_msg; - return es58x_rx_err_msg(netdev, rx_event_msg->error_code, rx_event_msg->event_code, get_unaligned_le64(&rx_event_msg->timestamp)); -- 2.34.1
