buildroot kernel panic

bbl loader
OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
Linux version 4.18.20 (aj@ubaura) (gcc version 7.3.0 (Buildroot 2018.11.2)) #1 SMP Mon Feb 25 10:28:02 IST 2019
initrd not found or empty - disabling initrd
Zone ranges:
  DMA32    [mem 0x0000000080200000-0x0000000087ffffff]
  Normal   [mem 0x0000000088000000-0x0000087fffffffff]
Movable zone start for each node
Early memory node ranges
  node   0: [mem 0x0000000080200000-0x0000000087ffffff]
Initmem setup node 0 [mem 0x0000000080200000-0x0000000087ffffff]
software IO TLB [mem 0x83e3d000-0x87e3d000] (64MB) mapped at [(____ptrval____)-(____ptrval____)]
elf_hwcap is 0x112d
percpu: Embedded 17 pages/cpu @(____ptrval____) s29144 r8192 d32296 u69632
Built 1 zonelists, mobility grouping on.  Total pages: 31815
Kernel command line: root=/dev/vda ro console=ttyS0
Dentry cache hash table entries: 16384 (order: 5, 131072 bytes)
Inode-cache hash table entries: 8192 (order: 4, 65536 bytes)
Sorting __ex_table...
Memory: 52476K/129024K available (5398K kernel code, 323K rwdata, 1729K rodata, 188K init, 806K bss, 76548K reserved, 0K cma-reserved)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
	RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=1.
RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
Console: colour dummy device 80x25
Calibrating delay loop (skipped), value calculated using timer frequency.. 20.00 BogoMIPS (lpj=40000)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 512 (order: 0, 4096 bytes)
Hierarchical SRCU implementation.
smp: Bringing up secondary CPUs ...
smp: Brought up 1 node, 1 CPU
devtmpfs: initialized
cpu cpu0: Error -2 creating of_node link
random: get_random_u32 called from bucket_table_alloc+0x6e/0x18c with crng_init=0
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
futex hash table entries: 256 (order: 2, 16384 bytes)
NET: Registered protocol family 16
vgaarb: loaded
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
NET: Registered protocol family 2
tcp_listen_portaddr_hash hash table entries: 256 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 1, 8192 bytes)
TCP bind hash table entries: 1024 (order: 2, 16384 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
UDP hash table entries: 256 (order: 1, 8192 bytes)
UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
workingset: timestamp_bits=62 max_order=14 bucket_order=0
NFS: Registering the id_resolver key type
Key type id_resolver registered
Key type id_legacy registered
nfs4filelayout_init: NFSv4 File Layout Driver Registering...
NET: Registered protocol family 38
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254)
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
io scheduler mq-deadline registered
io scheduler kyber registered
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
irq: no irq domain found for interrupt-controller@c000000 !
console [ttyS0] disabled
10000000.uart: ttyS0 at MMIO 0x10000000 (irq = 0, base_baud = 230400) is a 16550A
console [ttyS0] enabled
[drm] radeon kernel modesetting enabled.
loop: module loaded
virtio_blk: probe of virtio0 failed with error -22
libphy: Fixed MDIO Bus: probed
virtio_net: probe of virtio1 failed with error -22
e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ehci-pci: EHCI PCI platform driver
ehci-platform: EHCI generic platform driver
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ohci-pci: OHCI PCI platform driver
ohci-platform: OHCI generic platform driver
usbcore: registered new interface driver uas
usbcore: registered new interface driver usb-storage
mousedev: PS/2 mouse device common for all mice
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
NET: Registered protocol family 10
Segment Routing with IPv6
sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
NET: Registered protocol family 17
Key type dns_resolver registered
VFS: Cannot open root device "vda" or unknown-block(0,0): error -6
Please append a correct "root=" boot option; here are the available partitions:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.20 #1
Call Trace:
[<ffffffe000031046>] walk_stackframe+0x0/0xa0
[<ffffffe000031146>] show_stack+0x2a/0x34
[<ffffffe00055f8d0>] dump_stack+0x62/0x7c
[<ffffffe000035096>] panic+0xd6/0x1ec
[<ffffffe000000e86>] mount_block_root+0x182/0x240
[<ffffffe000001060>] mount_root+0x11c/0x134
[<ffffffe000001192>] prepare_namespace+0x11a/0x160
[<ffffffe000000afc>] kernel_init_freeable+0x18e/0x1ae
[<ffffffe000570898>] kernel_init+0x12/0xf0