Bug 2016782

So there's not a huge change between the last two kernels, a lot of it was audio which can be ruled out. Looking at the remainder I'm guessing it's a KVM change as I'm guessing this is a guest:

1ca7554d05ac038c98271f8968ed821266ecaa9c mm/thp: decrease nr_thps in file's mapping on THP split
79f9bc5843142b649575f887dccdf1c07ad75c20 mm/secretmem: fix NULL page->mapping dereference in page_is_secretmem()
032146cda85566abcd1c4884d9d23e4e30a07e9a vfs: check fd has read access in kernel_read_file_from_fd()
3ddd60268c24bcac9d744404cc277e9dc52fe6b6 mm, slub: fix incorrect memcg slab count for bulk free
67823a544414def2a36c212abadb55b23bcda00c mm, slub: fix potential use-after-free in slab_debugfs_fops
9037c57681d25e4dcc442d940d6dbe24dd31f461 mm, slub: fix potential memoryleak in kmem_cache_open()
899447f669da76cc3605665e1a95ee877bc464cc mm, slub: fix mismatch between reconstructed freelist depth and cnt
2127d22509aec3a83dffb2a3c736df7ba747a7ce mm, slub: fix two bugs in slab_debug_trace_open()
6d2aec9e123bb9c49cb5c7fc654f25f81e688e8c mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind()
5173ed72bcfcddda21ff274ee31c6472fa150f29 memblock: check memory total_size
a6a0251c6fce496744121b4e08c899f45270dbcc mm/migrate: fix CPUHP state to update node demotion order
76af6a054da4055305ddb28c5eb151b9ee4f74f9 mm/migrate: add CPU hotplug to demotion #ifdef
295be91f7ef0027fca2f2e4788e99731aa931834 mm/migrate: optimize hotplug-time demotion order updates
cb185d5f1ebf900f4ae3bf84cee212e6dd035aca userfaultfd: fix a race between writeprotect and exit_mmap()
8913970c19915bbe773d97d42989cd85b7fdc098 mm/userfaultfd: selftests: fix memory corruption with thp enabled
6e6a8ef088e1222cb1250942f51ad9c1ab219ab2 KVM: arm64: Release mmap_lock when using VM_SHARED with MTE
7615c2a514788559c6684234b8fc27f3a843c2c6 KVM: arm64: Report corrupted refcount at EL2
1d58a17ef54599506d44c45ac95be27273a4d2b1 KVM: arm64: Fix host stage-2 PGD refcount

(In reply to Peter Robinson from comment #1)
> So there's not a huge change between the last two kernels, a lot of it was
> audio which can be ruled out. Looking at the remainder I'm guessing it's a
> KVM change as I'm guessing this is a guest:
> 

Actually, assuming this is a guest, KVM changes can be ruled out, as guests don't enable KVM.

Also, it looks like an exception is occurring very early in Linux boot. I suspect we wouldn't even see anything with earlycon added to the kernel command line (but that's always worth a shot). My guess is that the initial page tables are messed up somehow, but I suggest we just blindly bisect to find the "bad" commit before we try to analyse anything.

So, on a libvirt/qemu/kvm/edk setup, its using ACPI so "earlycon" will honor the SPCR. So, putting earlycon by itself on the grub command line after the console=tty0 line and you should see something that is more helpful. Although, you might also try replacing the console=tty0 with console=ttyAMA0 too as, well the console can be problematic.

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