On Tue, Jun 28, 2016 at 10:39:15AM +0800, Fam Zheng wrote: > Userspace listens to the KOBJ_ADD uevent generated in add_disk. At that > point we haven't created the serial attribute file, therefore depending > on how fast udev reacts, the /dev/disk/by-id/ entry doesn't always get > created. > > This race condition can be easily reproduced by hot plugging a number of > virtio-blk disks. > > Also in systemd, there used to be a related workaround in udev rules > called 'WAIT_FOR="serial"', but it is removed in later versions. > > Now let's generate a KOBJ_CHANGE event after the attributes are ready.
The same race is present in other drivers as well, e.g. nvme. Please find a way to make this work properly without needing to hack every driver to send events manually.
