I'm running a remastered Tiny Core 4.2.1 in a virtual machine (KVM/libvirt/qemu-type) via direct kernel boot, mostly using virtio-type virtual disks. Somewhere between 10% and 50% of the time I boot a VM, one of the virtual disks is missing from /dev, though most if not all of the time it shows up in /proc/partitions. For example, on a recent test run, the VM was supposed to have four virtio disks: vda, vdb, vdc, and vdd. /proc/partitions listed all four, with reasonable-looking major and minor device numbers. However, in /dev, vdc was entirely missing.
Any suggestions for how to find the root cause of this problem? I would guess it's udev that is supposed to create the device nodes.
It would appear that for a workaround I could simply create the block device using the major and minor node numbers from /proc/partitions. Any ideas on whether that would work?