Facing kernel panic issue with Yocto: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Question

Scenario: I am working in Yocto linux project. I have created my own rootfs with tar.gz extension. And I have built linux kernel (using bitbake linux-kernel-rt). I am not able to load kernel and rootfs.

Can anyone explain what can be the issue.

Below is the log for the same.

VFS: Cannot open root device "mmcblk0p3" or unknown-block(0,0): error -6
Please append a correct "root=" boot option; here are the available partitions:
0100            4096 ram0
 (driver?)
0101            4096 ram1
 (driver?)
0102            4096 ram2
 (driver?)
0103            4096 ram3
 (driver?)
0104            4096 ram4
 (driver?)
0105            4096 ram5
 (driver?)
0106            4096 ram6
 (driver?)
0107            4096 ram7
 (driver?)
0108            4096 ram8
 (driver?)
0109            4096 ram9
 (driver?)
010a            4096 ram10
 (driver?)
010b            4096 ram11
 (driver?)
010c            4096 ram12
 (driver?)
010d            4096 ram13
 (driver?)
010e            4096 ram14
 (driver?)
010f            4096 ram15
 (driver?)
1f00           65536 mtdblock0
 (driver?)
1f01           65536 mtdblock1
 (driver?)
103:00000  250059096 nvme0n1
 (driver?)
  103:00001   52428800 nvme0n1p1 7a0121e2-01

  103:00002   52428800 nvme0n1p2 7a0121e2-02

  103:00003    1048576 nvme0n1p3 7a0121e2-03

  103:00004   52428800 nvme0n1p4 7a0121e2-04

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
Kernel Offset: 0x27c00000 from 0xffffffff81000000 (relocation range: 0xffffffff8

Answer 1

I had the same issue last week, and in my boot, I could see that the yocto boot was happening using a RAM Disk, and it's size was specified as 409600 (in my case and I believe the default value is 4096, which I see in your error here), and I got the same error you did when I tried installing more images onto the build. I'm guessing your issue might be the same. Try increasing the size of your RAM disk, and it's specified inside the recipes-bsp/grub/grub-efi file. When I increased the value, it worked, but it obviously is board specific, so do watch out.