Call Trace when adding vCPU to guest

[Linux regression tracking (Thorsten Leemhuis)]

Hi, Thorsten here, the Linux kernel's regression tracker.

I noticed a report about a regression in bugzilla.kernel.org.

Thomas, I wonder if it's caused by your topology changes. But it's just
a wild guess and I might be totally wrong there, so feel free to ignore
this mail. I already asked for a bit more log output and a bisection in
the ticket.

To quote from https://bugzilla.kernel.org/show_bug.cgi?id=218698

> Environment:
> 
> Host OS: CentOS 9
> Host kernel: 6.9.0-rc1
> KVM commit: 9bc60f73
> Qemu commit: e5c6528d
> Guest kernel: 6.9-rc2
> Guest commit: 39cd87c4eb2b893354f3b850f916353f2658ae6f
> Guest repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> 
> 
> Bug detail description: 
> 
> When hot adding a vCPU to the guest, the guest happens Call Trace and reboot.
> 
> Latest successful guest kernel version: 6.8.0-rc7 (commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72).
> 
> 
> Reproduce steps: 
> 
> 1. Create guest:
> 
> qemu-system-x86_64 -accel kvm -cpu host -smp 4,maxcpus=128 -drive file=/share/xvs/var/tmp-img_vcpu_hot_add_1712412537,if=none,id=virtio-disk0 -device virtio-blk-pci,drive=virtio-disk0,bootindex=0 -m 4096 -monitor pty -daemonize -vnc :16147 -device virtio-net-pci,netdev=nic0,mac=00:c0:82:16:fa:b0 -netdev tap,id=nic0,br=virbr0,helper=/usr/local/libexec/qemu-bridge-helper,vhost=on
> 
> 2. Add vCPU to guest
> 
> echo 'device_add driver=host-x86_64-cpu,socket-id=0,core-id=4,thread-id=0' > /dev/pts/2
> 
> cat /dev/pts/2
> 
> 
> Error log: 
> 
> [   49.782913] Call Trace:
> [   49.783039]  <TASK>
> [   49.783147]  ? __die+0x24/0x70
> [   49.783309]  ? page_fault_oops+0x82/0x150
> [   49.783518]  ? kernelmode_fixup_or_oops+0x84/0x110
> [   49.783753]  ? exc_page_fault+0xb9/0x160
> [   49.783948]  ? asm_exc_page_fault+0x26/0x30
> [   49.784144]  ? cpu_update_apic+0x1c/0x70
> [   49.784327]  generic_processor_info+0x7e/0x160
> [   49.784541]  acpi_register_lapic+0x19/0x80
> [   49.784732]  acpi_map_cpu+0x26/0x90
> [   49.784896]  acpi_processor_get_info+0x256/0x490
> [   49.785344]  acpi_processor_add+0xb9/0x1f0
> [   49.785760]  acpi_bus_attach+0x13b/0x220
> [   49.786158]  acpi_bus_scan+0x7e/0x1e0
> [   49.786548]  acpi_device_hotplug+0x198/0x2b0
> [   49.786963]  acpi_hotplug_work_fn+0x1e/0x30
> [   49.787363]  process_one_work+0x159/0x370
> [   49.787790]  worker_thread+0x302/0x420
> [   49.788184]  ? __pfx_worker_thread+0x10/0x10
> [   49.788592]  kthread+0xe3/0x120
> [   49.788955]  ? __pfx_kthread+0x10/0x10
> [   49.789335]  ret_from_fork+0x31/0x50
> [   49.789720]  ? __pfx_kthread+0x10/0x10
> [   49.790100]  ret_from_fork_asm+0x1b/0x30
> [   49.790491]  </TASK>

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

P.S.: let me use this mail to also add the report to the list of tracked
regressions to ensure it's doesn't fall through the cracks:

#regzbot introduced: v6.8-rc7..v6.9-rc2
#regzbot title: Call Trace when adding vCPU to guest
#regzbot from: "Ma, XiangfeiX" <xiangfeix.ma@xxxxxxxxx>
#regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=218698
#regzbot ignore-activity