From: Leon Romanovsky <leonro@xxxxxxxxxxxx> commit b79656ed44c6865e17bcd93472ec39488bcc4984 upstream. Systemd triggers the following warning during IPoIB device load: mlx5_core 0000:00:0c.0 ib0: "systemd-udevd" wants to know my dev_id. Should it look at dev_port instead? See Documentation/ABI/testing/sysfs-class-net for more info. This is caused due to user space attempt to differentiate old systems without dev_port and new systems with dev_port. In case dev_port will be zero, the systemd will try to read dev_id instead. There is no need to print a warning in such case, because it is valid situation and it is needed to ensure systemd compatibility with old kernels. Link: https://github.com/systemd/systemd/blob/master/src/udev/udev-builtin-net_id.c#L358 Cc: <stable@xxxxxxxxxxxxxxx> # 4.19 Fixes: f6350da41dc7 ("IB/ipoib: Log sysfs 'dev_id' accesses from userspace") Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/infiniband/ulp/ipoib/ipoib_main.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -2402,7 +2402,18 @@ static ssize_t dev_id_show(struct device { struct net_device *ndev = to_net_dev(dev); - if (ndev->dev_id == ndev->dev_port) + /* + * ndev->dev_port will be equal to 0 in old kernel prior to commit + * 9b8b2a323008 ("IB/ipoib: Use dev_port to expose network interface + * port numbers") Zero was chosen as special case for user space + * applications to fallback and query dev_id to check if it has + * different value or not. + * + * Don't print warning in such scenario. + * + * https://github.com/systemd/systemd/blob/master/src/udev/udev-builtin-net_id.c#L358 + */ + if (ndev->dev_port && ndev->dev_id == ndev->dev_port) netdev_info_once(ndev, "\"%s\" wants to know my dev_id. Should it look at dev_port instead? See Documentation/ABI/testing/sysfs-class-net for more info.\n", current->comm);