Another partner reported below which might be similar. The kernel version is 5.4.0-26-generic which is not lasted, so they was asked to upgrade and verify again.
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] Call Trace:
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] set_cpu_sibling_map+0x159/0x590
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] start_secondary+0x6f/0x1c0
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] secondary_startup_64+0xa4/0xb0
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] ---[ end trace 4403443dce444e18 ]---
Another partner reported below which might be similar. The kernel version is 5.4.0-26-generic which is not lasted, so they was asked to upgrade and verify again.
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] Call Trace: sibling_ map+0x159/ 0x590 +0x6f/0x1c0 startup_ 64+0xa4/ 0xb0
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] set_cpu_
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] start_secondary
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] secondary_
Aug 31 18:47:45 ubuntu kernel: [ 2.999509] ---[ end trace 4403443dce444e18 ]---