Created attachment 306112 [details] guest error log 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>
Reminder: this bug tracker is most likely the wrong place for this sort of bug. And I'm not a developer involved in any of the subsystems that might cause this, so anything I might suggest might be sending you sideways. I fear we might a bisection (see https://docs.kernel.org/admin-guide/verify-bugs-and-bisect-regressions.html) in the guest to pin this down. But I will prod a developer that recently changed something that might cause this, maybe he will take a look
Ohh, and having a bit more log output from right before the backtrace is shown might be good as well.
Like fixed in rc4, see https://lore.kernel.org/all/87bk6h49tq.ffs@tglx/ Side note: Artem reassigned this to Virtualization, I don't think that was wise, but whatever, I don't care bout bugzilla.
I can reproduce as well. But the callstack is different. It finally reaches at topo_set_cpuids(). /home/zhang/kvm/qemu-8.2.0/build/qemu-system-x86_64 \ -hda disk.qcow2 -m 8G -smp 4,maxcpus=128 -vnc :5 -enable-kvm -cpu host \ -netdev user,id=user0,hostfwd=tcp::5025-:22 \ -device virtio-net-pci,netdev=user0,id=net0,mac=12:14:10:12:14:16,bus=pci.0,addr=0x3 \ -kernel /home/zhang/img/debug/mainline-linux/arch/x86_64/boot/bzImage \ -append "root=/dev/sda3 init=/sbin/init text loglevel=7 console=ttyS0" \ -monitor stdio (qemu) device_add driver=host-x86_64-cpu,socket-id=0,core-id=4,thread-id=0 [ 27.060885] BUG: unable to handle page fault for address: ffffffff83a69778 [ 27.061954] #PF: supervisor write access in kernel mode [ 27.062604] #PF: error_code(0x0003) - permissions violation [ 27.063286] PGD 40c49067 P4D 40c49067 PUD 40c4a063 PMD 102213063 PTE 8000000040a69021 [ 27.064273] Oops: 0003 [#1] PREEMPT SMP PTI [ 27.064799] CPU: 2 PID: 39 Comm: kworker/u256:1 Not tainted 6.9.0-rc3 #1 [ 27.065611] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 27.066992] Workqueue: kacpi_hotplug acpi_hotplug_work_fn [ 27.067669] RIP: 0010:topo_set_cpuids+0x26/0x70 [ 27.068242] Code: 90 90 90 90 48 8b 05 d9 bd da 01 48 85 c0 74 31 89 ff 48 8d 04 b8 89 30 48 8b 05 bd bd da 01 48 85 c0 74 3c 48 8d 04 b8 89 10 <f0> 48 0f ab 3d 79 9e 97 01 f0 48 0f ab 3d 40 03 df 01 c3 cc cc cc [ 27.070471] RSP: 0018:ffffc3980034bc28 EFLAGS: 00010286 [ 27.071130] RAX: ffffa0bbb6f15160 RBX: 0000000000000004 RCX: 0000000000000040 [ 27.072004] RDX: 0000000000000004 RSI: 0000000000000004 RDI: 0000000000000004 [ 27.072858] RBP: ffffa0ba80d68540 R08: 000000000001d4c0 R09: 0000000000000001 [ 27.073713] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000004 [ 27.074565] R13: ffffa0ba883b6c10 R14: ffffa0ba809a9040 R15: 0000000000000000 [ 27.075418] FS: 0000000000000000(0000) GS:ffffa0bbb6e80000(0000) knlGS:0000000000000000 [ 27.076424] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.077121] CR2: ffffffff83a69778 CR3: 000000010f946006 CR4: 0000000000370ef0 [ 27.077976] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 27.078830] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 27.079685] Call Trace: [ 27.080031] <TASK> [ 27.080341] ? __die+0x1f/0x70 [ 27.080755] ? page_fault_oops+0x17b/0x490 [ 27.081305] ? search_exception_tables+0x37/0x50 [ 27.081897] ? exc_page_fault+0xba/0x160 [ 27.082402] ? asm_exc_page_fault+0x26/0x30 [ 27.082929] ? topo_set_cpuids+0x26/0x70 [ 27.083432] topology_hotplug_apic+0x54/0xa0 [ 27.083979] acpi_map_cpu+0x1c/0x80 [ 27.084437] acpi_processor_add+0x361/0x630 [ 27.084968] acpi_bus_attach+0x151/0x230 [ 27.085473] ? __pfx_acpi_dev_for_one_check+0x10/0x10 [ 27.086091] device_for_each_child+0x68/0xb0 [ 27.086638] acpi_dev_for_each_child+0x37/0x60 [ 27.087197] ? __pfx_acpi_bus_attach+0x10/0x10 [ 27.087757] acpi_bus_attach+0x89/0x230 [ 27.088251] acpi_bus_scan+0x77/0x1f0 [ 27.088753] acpi_scan_rescan_bus+0x3c/0x70 [ 27.089300] acpi_device_hotplug+0x3a3/0x480 [ 27.089840] acpi_hotplug_work_fn+0x19/0x30 [ 27.090369] process_one_work+0x14c/0x360 [ 27.090880] worker_thread+0x2c5/0x3d0 [ 27.091387] ? __pfx_worker_thread+0x10/0x10 [ 27.091941] kthread+0xd3/0x100 [ 27.092361] ? __pfx_kthread+0x10/0x10 [ 27.092843] ret_from_fork+0x2f/0x50 [ 27.093309] ? __pfx_kthread+0x10/0x10 [ 27.093788] ret_from_fork_asm+0x1a/0x30 [ 27.094293] </TASK> [ 27.094601] Modules linked in: [ 27.095007] CR2: ffffffff83a69778 [ 27.095444] ---[ end trace 0000000000000000 ]--- [ 27.096018] RIP: 0010:topo_set_cpuids+0x26/0x70 [ 27.096590] Code: 90 90 90 90 48 8b 05 d9 bd da 01 48 85 c0 74 31 89 ff 48 8d 04 b8 89 30 48 8b 05 bd bd da 01 48 85 c0 74 3c 48 8d 04 b8 89 10 <f0> 48 0f ab 3d 79 9e 97 01 f0 48 0f ab 3d 40 03 df 01 c3 cc cc cc [ 27.098808] RSP: 0018:ffffc3980034bc28 EFLAGS: 00010286 [ 27.099452] RAX: ffffa0bbb6f15160 RBX: 0000000000000004 RCX: 0000000000000040 [ 27.100305] RDX: 0000000000000004 RSI: 0000000000000004 RDI: 0000000000000004 [ 27.101153] RBP: ffffa0ba80d68540 R08: 000000000001d4c0 R09: 0000000000000001 [ 27.102141] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000004 [ 27.102995] R13: ffffa0ba883b6c10 R14: ffffa0ba809a9040 R15: 0000000000000000 [ 27.103851] FS: 0000000000000000(0000) GS:ffffa0bbb6e80000(0000) knlGS:0000000000000000 [ 27.104857] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.105559] CR2: ffffffff83a69778 CR3: 000000010f946006 CR4: 0000000000370ef0 [ 27.106411] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 27.107264] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------------- I am not able to reproduce with the below: x86/topology: Don't update cpu_possible_map in topo_set_cpuids() https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/urgent&id=a9025cd1c673a8d6eefc79d911075b8b452eba8f
Please reopen if this is reproducible in 6.9-RC4.
This issue cannot reproduce in the latest linux kernel. Host OS: CentOS 9 Host kernel: 6.9.0-rc1 KVM commit: 1ab157ce Qemu commit: 0c2a3807 Guest linux kernel: 6.9.0-rc4 Guest linux commit: 96fca68c4fbf77a8185eb10f7557e23352732ea2