Re: [PATCH] scsi: Don't wait for completion of in-flight requests

From: Qiang Ma
Date: Wed Dec 04 2024 - 04:11:14 EST

On Tue, 3 Dec 2024 22:36:47 +0800
Ming Lei <ming.lei@xxxxxxxxxx> wrote:

> On Tue, Dec 03, 2024 at 09:21:04PM +0800, Qiang Ma wrote:
> > On Wed, 27 Nov 2024 23:20:28 +0800
> > Ming Lei <ming.lei@xxxxxxxxxx> wrote:
> >
> > > On Wed, Nov 27, 2024 at 10:04:37PM +0800, Qiang Ma wrote:
> > > > On Tue, 26 Nov 2024 22:15:02 +0800
> > > > Ming Lei <ming.lei@xxxxxxxxxx> wrote:
> > > >
> > > > > On Tue, Nov 26, 2024 at 07:50:08PM +0800, Qiang Ma wrote:
> > > > > > Problem:
> > > > > > When the system disk uses the scsi disk bus, The main
> > > > > > qemu command line includes:
> > > > > > ...
> > > > > > -device virtio-scsi-pci,id=scsi0 \
> > > > > > -device scsi-hd,scsi-id=1,drive=drive-virtio-disk
> > > > > > -drive
> > > > > > id=drive-virtio-disk,if=none,file=/home/kvm/test.qcow2 ...
> > > > > >
> > > > > > The dmesg log is as follows::
> > > > > >
> > > > > > [ 50.304591][ T4382] sd 0:0:0:0: [sda] Synchronizing SCSI
> > > > > > cache [ 50.377002][ T4382] kexec_core: Starting new
> > > > > > kernel
> > >
> > > Why is one new kernel started? what event triggers kernel_kexec()?
> > >
> > > machine_shutdown() follows, probably the scsi controller is dead.
> > >
> >
> > Yes, triggered by kexec, manually execute the following command:
> > kexec -l /boot/vmlinuz-6.6.0+ --reuse-cmdline
> > --initrd=/boot/initramfs-6.6.0+.img kexec -e
> >
> > > > > > [ 50.669775][ T194] psci: CPU1 killed (polled 0 ms)
> > > > > > [ 50.849665][ T194] psci: CPU2 killed (polled 0 ms)
> > > > > > [ 51.109625][ T194] psci: CPU3 killed (polled 0 ms)
> > > > > > [ 51.319594][ T194] psci: CPU4 killed (polled 0 ms)
> > > > > > [ 51.489667][ T194] psci: CPU5 killed (polled 0 ms)
> > > > > > [ 51.709582][ T194] psci: CPU6 killed (polled 0 ms)
> > > > > > [ 51.949508][ T10] psci: CPU7 killed (polled 0 ms)
> > > > > > [ 52.139499][ T10] psci: CPU8 killed (polled 0 ms)
> > > > > > [ 52.289426][ T10] psci: CPU9 killed (polled 0 ms)
> > > > > > [ 52.439552][ T10] psci: CPU10 killed (polled 0 ms)
> > > > > > [ 52.579525][ T10] psci: CPU11 killed (polled 0 ms)
> > > > > > [ 52.709501][ T10] psci: CPU12 killed (polled 0 ms)
> > > > > > [ 52.819509][ T194] psci: CPU13 killed (polled 0 ms)
> > > > > > [ 52.919509][ T194] psci: CPU14 killed (polled 0 ms)
> > > > > > [ 243.214009][ T115] INFO: task kworker/0:1:10 blocked for
> > > > > > more than 122 seconds. [ 243.214810][ T115] Not
> > > > > > tainted 6.6.0+ #1 [ 243.215517][ T115] "echo 0
> > > > > > > /proc/sys/kernel/hung_task_timeout_secs" disables this
> > > > > > > message. [ 243.216390][ T115] task:kworker/0:1
> > > > > > > state:D stack:0 pid:10 ppid:2 flags:0x00000008
> > > > > > [ 243.217299][ T115] Workqueue: events vmstat_shepherd
> > > > > > [ 243.217816][ T115] Call trace:
> > > > > > [ 243.218133][ T115] __switch_to+0x130/0x1e8
> > > > > > [ 243.218568][ T115] __schedule+0x660/0xcf8
> > > > > > [ 243.219013][ T115] schedule+0x58/0xf0
> > > > > > [ 243.219402][ T115] percpu_rwsem_wait+0xb0/0x1d0
> > > > > > [ 243.219880][ T115] __percpu_down_read+0x40/0xe0
> > > > > > [ 243.220353][ T115] cpus_read_lock+0x5c/0x70
> > > > > > [ 243.220795][ T115] vmstat_shepherd+0x40/0x140
> > > > > > [ 243.221250][ T115] process_one_work+0x170/0x3c0
> > > > > > [ 243.221726][ T115] worker_thread+0x234/0x3b8
> > > > > > [ 243.222176][ T115] kthread+0xf0/0x108
> > > > > > [ 243.222564][ T115] ret_from_fork+0x10/0x20
> > > > > > ...
> > > > > > [ 243.254080][ T115] INFO: task kworker/0:2:194 blocked
> > > > > > for more than 122 seconds. [ 243.254834][ T115] Not
> > > > > > tainted 6.6.0+ #1 [ 243.255529][ T115] "echo 0
> > > > > > > /proc/sys/kernel/hung_task_timeout_secs" disables this
> > > > > > > message. [ 243.256378][ T115] task:kworker/0:2
> > > > > > > state:D stack:0 pid:194 ppid:2 flags:0x00000008
> > > > > > [ 243.257284][ T115] Workqueue: events work_for_cpu_fn
> > > > > > [ 243.257793][ T115] Call trace:
> > > > > > [ 243.258111][ T115] __switch_to+0x130/0x1e8
> > > > > > [ 243.258541][ T115] __schedule+0x660/0xcf8
> > > > > > [ 243.258971][ T115] schedule+0x58/0xf0
> > > > > > [ 243.259360][ T115] schedule_timeout+0x280/0x2f0
> > > > > > [ 243.259832][ T115] wait_for_common+0xcc/0x2d8
> > > > > > [ 243.260287][ T115] wait_for_completion+0x20/0x38
> > > > > > [ 243.260767][ T115] cpuhp_kick_ap+0xe8/0x278
> > > > > > [ 243.261207][ T115] cpuhp_kick_ap_work+0x5c/0x188
> > > > > > [ 243.261688][ T115] _cpu_down+0x120/0x378
> > > > > > [ 243.262103][ T115] __cpu_down_maps_locked+0x20/0x38
> > > > > > [ 243.262609][ T115] work_for_cpu_fn+0x24/0x40
> > > > > > [ 243.263059][ T115] process_one_work+0x170/0x3c0
> > > > > > [ 243.263533][ T115] worker_thread+0x234/0x3b8
> > > > > > [ 243.263981][ T115] kthread+0xf0/0x108
> > > > > > [ 243.264405][ T115] ret_from_fork+0x10/0x20
> > > > > > [ 243.264846][ T115] INFO: task kworker/15:2:639 blocked
> > > > > > for more than 122 seconds. [ 243.265602][ T115] Not
> > > > > > tainted 6.6.0+ #1 [ 243.266296][ T115] "echo 0
> > > > > > > /proc/sys/kernel/hung_task_timeout_secs" disables this
> > > > > > > message. [ 243.267143][ T115] task:kworker/15:2
> > > > > > > state:D stack:0 pid:639 ppid:2 flags:0x00000008
> > > > > > [ 243.268044][ T115] Workqueue: events_freezable_power_
> > > > > > disk_events_workfn [ 243.268727][ T115] Call trace:
> > > > > > [ 243.269051][ T115] __switch_to+0x130/0x1e8
> > > > > > [ 243.269481][ T115] __schedule+0x660/0xcf8
> > > > > > [ 243.269903][ T115] schedule+0x58/0xf0
> > > > > > [ 243.270293][ T115] schedule_timeout+0x280/0x2f0
> > > > > > [ 243.270763][ T115] io_schedule_timeout+0x50/0x70
> > > > > > [ 243.271245][ T115]
> > > > > > wait_for_common_io.constprop.0+0xb0/0x298
> > > > > > [ 243.271830][ T115] wait_for_completion_io+0x1c/0x30
> > > > > > [ 243.272335][ T115] blk_execute_rq+0x1d8/0x278
> > > > > > [ 243.272793][ T115] scsi_execute_cmd+0x114/0x238
> > > > > > [ 243.273267][ T115] sr_check_events+0xc8/0x310 [sr_mod]
> > > > > > [ 243.273808][ T115] cdrom_check_events+0x2c/0x50 [cdrom]
> > > > > > [ 243.274408][ T115] sr_block_check_events+0x34/0x48
> > > > > > [sr_mod] [ 243.274994][ T115]
> > > > > > disk_check_events+0x44/0x1b0 [ 243.275468][ T115]
> > > > > > disk_events_workfn+0x20/0x38 [ 243.275939][ T115]
> > > > > > process_one_work+0x170/0x3c0 [ 243.276410][ T115]
> > > > > > worker_thread+0x234/0x3b8 [ 243.276855][ T115]
> > > > > > kthread+0xf0/0x108 [ 243.277241][ T115]
> > > > > > ret_from_fork+0x10/0x20
> > > > >
> > > > > Question is why this scsi command can't be completed?
> > > > >
> > > > > When blk_mq_hctx_notify_offline() is called, the CPU isn't
> > > > > shutdown yet, and it still can handle interrupt of this SCSI
> > > > > command.
> > > > >
> > > > >
> > > > > Thanks,
> > > > > Ming
> > > > >
> > > > >
> > > > Sorry, at the moment I don't know why it can't be finished,
> > > > just provides a solution like loop and dm-rq.
> > > >
> > > > Currently see the call stack:
> > > > => blk_mq_run_hw_queue
> > > > =>__blk_mq_sched_restart
> > > > => blk_mq_run_hw_queue
> > > > => __blk_mq_sched_restart
> > > > => __blk_mq_free_request
> > > > => blk_mq_free_request
> > > > => blk_mq_end_request
> > > > => blk_flush_complete_seq
> > > > => flush_end_io
> > > > => __blk_mq_end_request
> > > > => scsi_end_request
> > > > => scsi_io_completion
> > > > => scsi_finish_command
> > > > => scsi_complete
> > > > => blk_mq_complete_request
> > > > => scsi_done_internal
> > > > => scsi_done
> > > > => virtscsi_complete_cmd
> > > > => virtscsi_req_done
> > > > => vring_interrupt
> > > >
> > > > In finction blk_mq_run_hw_queue():
> > > > __blk_mq_run_dispatch_ops(hctx->queue, false,
> > > > need_run = !blk_queue_quiesced(hctx->queue) &&
> > > > blk_mq_hctx_has_pending(hctx));
> > > >
> > > > if (!need_run)
> > > > return;
> > > >
> > > > Come here and return directly.
> > >
> > > Does blk_queue_quiesced() return true?
> > >
> >
> > blk_queue_quiesced() return false
> >
> > Sorry, the calltrace above is not the one that is stuck this time.
> > The hang is caused by the wait_for_completion_io(), in
> > blk_execute_rq():
> >
> > blk_status_t blk_execute_rq(struct request *rq, bool at_head)
> > {
> > ...
> > rq->end_io_data = &wait;
> > rq->end_io = blk_end_sync_rq;
> > ...
> > blk_account_io_start(rq);
> > blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD :
> > 0); blk_mq_run_hw_queue(hctx, false);
> >
> > if (blk_rq_is_poll(rq)) {
> > blk_rq_poll_completion(rq, &wait.done);
> > } else {
> > ...
> > wait_for_completion_io(&wait.done);
> > }
> > }
> >
> > In this case, end_io is blk_end_sync_rq, which is not executed.
> >
> > The process for sending scsi commands is as follows:
> >
> > kworker/7:1-134 [007] ..... 32.772727: vp_notify
> > <-virtqueue_notify kworker/7:1-134 [007] .....
> > 32.772729: <stack trace> => vp_notify
> > => virtqueue_notify
> > => virtscsi_add_cmd
> > => virtscsi_queuecommand
> > => scsi_dispatch_cmd
> > => scsi_queue_rq
> > => blk_mq_dispatch_rq_list
> > => __blk_mq_sched_dispatch_requests
> > => blk_mq_sched_dispatch_requests
> > => blk_mq_run_hw_queue
> > => blk_execute_rq
> > => scsi_execute_cmd
> > => sr_check_events
> > => cdrom_check_events
> > => sr_block_check_events
> > => disk_check_events
> > => disk_events_workfn
> > => process_one_work
> > => worker_thread
> > => kthread
> > => ret_from_fork
> >
> > In qemu:
> > static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
> > {
> > ...
> > do {
> > if (suppress_notifications) {
> > virtio_queue_set_notification(vq, 0);
> > }
> > ...
> > } while (ret != -EINVAL && !virtio_queue_empty(vq));
> > ...
> > QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
> > virtio_scsi_handle_cmd_req_submit(s, req);
> > }
> > }
> >
> > virtio_queue_empty() always return true.
> >
> > As a result, the virtio_scsi_handle_cmd_req_submit() was not
> > executed, and the io command was never submitted.
> >
> > The reason is that virtio_device_disabled returns true in
> > virtio_queue_split_empty, the code is as follows:
> >
> > int virtio_queue_empty(VirtQueue *vq)
> > {
> > if (virtio_vdev_has_feature(vq->vdev,
> > VIRTIO_F_RING_PACKED)) { return virtio_queue_packed_empty(vq);
> > } else {
> > return virtio_queue_split_empty(vq);
> > }
> > }
> >
> > static int virtio_queue_split_empty(VirtQueue *vq)
> > {
> > bool empty;
> >
> > if (virtio_device_disabled(vq->vdev)) {
> > return 1;
> > ...
> > }
> >
> > This function was introduced in the following patch:
> >
> > commit 9d7bd0826f2d19f88631ad7078662668148f7b5f
> > Author: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
> > Date: Tue Nov 19 18:50:03 2019 -0600
> >
> > virtio-pci: disable vring processing when bus-mastering is
> > disabled
>
> OK, then it is obviously one qemu issue, and it can explain why IO
> isn't completed in this case.
>
>

However, in fact, the current pci-master state is disabled, it is
shutdown by executing the syscore_shutdown() in kernel_kexec(), and the
call stack is as follows:
kernel_kexec
=> syscore_shutdown
=> ops->shutdown
=> pci_device_shutdown
=> pci_clear_master
=> __pci_set_master

Therefore, qemu determines the pci-master status and disable
virtio-pci when tthe state of the pci-master is disabled.

static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
uint32_t val, int len)
{
...

if (!(pci_dev->config[PCI_COMMAND] & PCI_COMMAND_MASTER)) {
virtio_set_disabled(vdev, true);
virtio_pci_stop_ioeventfd(proxy);
virtio_set_status(vdev,
vdev->status&~VIRTIO_CONFIG_S_DRIVER_OK);
} else {
virtio_set_disabled(vdev, false);
}
...
}

After opening pci_dbg of initcall_debug and pci.c,
the kernel log is as follows:

[root@localhost ~]# [ 41.490716][ T8227] platform
regulatory.0: shutdown [ 41.491726][ T8227] sd 0:0:0:0: shutdown
[ 41.492471][ T8227] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 41.496945][ T8227] snd_aloop snd_aloop.0: shutdown
[ 41.497885][ T8227] platform smccc_trng: shutdown
[ 41.498797][ T8227] platform platform-framebuffer.0: shutdown
[ 41.499874][ T8227] alarmtimer alarmtimer.0.auto: shutdown
[ 41.500905][ T8227] usb usb2-port15: shutdown
[ 41.501713][ T8227] usb usb2-port14: shutdown
[ 41.502527][ T8227] usb usb2-port13: shutdown
[ 41.503367][ T8227] usb usb2-port12: shutdown
[ 41.504188][ T8227] usb usb2-port11: shutdown
[ 41.505002][ T8227] usb usb2-port10: shutdown
[ 41.505816][ T8227] usb usb2-port9: shutdown
[ 41.506615][ T8227] usb usb2-port8: shutdown
[ 41.507409][ T8227] usb usb2-port7: shutdown
[ 41.508205][ T8227] usb usb2-port6: shutdown
[ 41.509053][ T8227] usb usb2-port5: shutdown
[ 41.509853][ T8227] usb usb2-port4: shutdown
[ 41.510652][ T8227] usb usb2-port3: shutdown
[ 41.511448][ T8227] usb usb2-port2: shutdown
[ 41.512249][ T8227] usb usb2-port1: shutdown
[ 41.513053][ T8227] usb usb1-port15: shutdown
[ 41.513836][ T8227] usb usb1-port14: shutdown
[ 41.514622][ T8227] usb usb1-port13: shutdown
[ 41.515408][ T8227] usb usb1-port12: shutdown
[ 41.516191][ T8227] usb usb1-port11: shutdown
[ 41.516970][ T8227] usb usb1-port10: shutdown
[ 41.517754][ T8227] usb usb1-port9: shutdown
[ 41.518519][ T8227] usb usb1-port8: shutdown
[ 41.519341][ T8227] usb usb1-port7: shutdown
[ 41.520102][ T8227] usb usb1-port6: shutdown
[ 41.520868][ T8227] usb usb1-port5: shutdown
[ 41.521630][ T8227] usb usb1-port4: shutdown
[ 41.522396][ T8227] usb usb1-port3: shutdown
[ 41.523169][ T8227] usb usb1-port2: shutdown
[ 41.523929][ T8227] usb usb1-port1: shutdown
[ 41.524698][ T8227] platform Fixed MDIO bus.0: shutdown
[ 41.525697][ T8227] kgdboc kgdboc: shutdown
[ 41.526451][ T8227] serial8250 serial8250: shutdown
[ 41.527335][ T8227] pciehp 0000:00:01.7:pcie004: shutdown
[ 41.528295][ T8227] aer 0000:00:01.7:pcie002: shutdown
[ 41.529274][ T8227] pcie_pme 0000:00:01.7:pcie001: shutdown
[ 41.530278][ T8227] pciehp 0000:00:01.6:pcie004: shutdown
[ 41.531243][ T8227] aer 0000:00:01.6:pcie002: shutdown
[ 41.532161][ T8227] pcie_pme 0000:00:01.6:pcie001: shutdown
[ 41.533164][ T8227] pciehp 0000:00:01.5:pcie004: shutdown
[ 41.534132][ T8227] aer 0000:00:01.5:pcie002: shutdown
[ 41.535052][ T8227] pcie_pme 0000:00:01.5:pcie001: shutdown
[ 41.536051][ T8227] pciehp 0000:00:01.4:pcie004: shutdown
[ 41.537011][ T8227] aer 0000:00:01.4:pcie002: shutdown
[ 41.537928][ T8227] pcie_pme 0000:00:01.4:pcie001: shutdown
[ 41.538971][ T8227] pciehp 0000:00:01.3:pcie004: shutdown
[ 41.539939][ T8227] aer 0000:00:01.3:pcie002: shutdown
[ 41.540855][ T8227] pcie_pme 0000:00:01.3:pcie001: shutdown
[ 41.541847][ T8227] pciehp 0000:00:01.2:pcie004: shutdown
[ 41.542823][ T8227] aer 0000:00:01.2:pcie002: shutdown
[ 41.543743][ T8227] pcie_pme 0000:00:01.2:pcie001: shutdown
[ 41.544742][ T8227] pciehp 0000:00:01.1:pcie004: shutdown
[ 41.545705][ T8227] aer 0000:00:01.1:pcie002: shutdown
[ 41.546625][ T8227] pcie_pme 0000:00:01.1:pcie001: shutdown
[ 41.547616][ T8227] pciehp 0000:00:01.0:pcie004: shutdown
[ 41.548579][ T8227] aer 0000:00:01.0:pcie002: shutdown
[ 41.549571][ T8227] pcie_pme 0000:00:01.0:pcie001: shutdown
[ 41.550645][ T8227] system 00:00: shutdown
[ 41.551381][ T8227] platform efivars.0: shutdown
[ 41.552208][ T8227] rtc-efi rtc-efi.0: shutdown
[ 41.553029][ T8227] platform PNP0C0C:00: shutdown
[ 41.553865][ T8227] acpi-ged ACPI0013:00: shutdown
[ 41.554829][ T8227] ahci 0000:09:01.0: shutdown
[ 41.555911][ T8227] ahci 0000:09:01.0: disabling bus mastering
[ 41.557683][ T8227] shpchp 0000:08:00.0: shutdown
[ 41.558555][ T8227] shpchp 0000:08:00.0: disabling bus mastering
[ 41.560917][ T8227] xhci_hcd 0000:07:00.0: shutdown
[ 41.563837][ T8227] virtio-pci 0000:06:00.0: shutdown
[ 41.564769][ T8227] virtio-pci 0000:06:00.0: disabling bus mastering
[ 41.566490][ T8227] virtio-pci 0000:05:00.0: shutdown
[ 41.567436][ T8227] virtio-pci 0000:05:00.0: disabling bus mastering
[ 41.569188][ T8227] virtio-pci 0000:04:00.0: shutdown
[ 41.570126][ T8227] virtio-pci 0000:04:00.0: disabling bus mastering
[ 41.571903][ T8227] virtio-pci 0000:03:00.0: shutdown
[ 41.572856][ T8227] virtio-pci 0000:03:00.0: disabling bus mastering
[ 41.576969][ T8227] virtio-pci 0000:02:00.0: shutdown
[ 41.578341][ T8227] virtio-pci 0000:02:00.0: disabling bus mastering
[ 41.902816][ T8227] virtio-pci 0000:01:00.0: shutdown
[ 41.905600][ T8227] virtio-pci 0000:01:00.0: disabling bus mastering
[ 41.942715][ T8227] pcieport 0000:00:01.7: shutdown
[ 41.944723][ T8227] pcieport 0000:00:01.7: disabling bus mastering
[ 41.946667][ T8227] pcieport 0000:00:01.6: shutdown
[ 41.948481][ T8227] pcieport 0000:00:01.6: disabling bus mastering
[ 41.950693][ T8227] pcieport 0000:00:01.5: shutdown
[ 41.953068][ T8227] pcieport 0000:00:01.5: disabling bus mastering
[ 41.955722][ T8227] pcieport 0000:00:01.4: shutdown
[ 41.957888][ T8227] pcieport 0000:00:01.4: disabling bus mastering
[ 41.960272][ T8227] pcieport 0000:00:01.3: shutdown
[ 41.962422][ T8227] pcieport 0000:00:01.3: disabling bus mastering
[ 41.964726][ T8227] pcieport 0000:00:01.2: shutdown
[ 41.967348][ T8227] pcieport 0000:00:01.2: disabling bus mastering
[ 41.969762][ T8227] pcieport 0000:00:01.1: shutdown
[ 41.972004][ T8227] pcieport 0000:00:01.1: disabling bus mastering
[ 41.974365][ T8227] pcieport 0000:00:01.0: shutdown
[ 41.977924][ T8227] pcieport 0000:00:01.0: disabling bus mastering
[ 41.979974][ T8227] pci 0000:00:00.0: shutdown
[ 41.980836][ T8227] platform LNRO0005:1f: shutdown
[ 41.981739][ T8227] platform LNRO0005:1e: shutdown
[ 41.982654][ T8227] platform LNRO0005:1d: shutdown
[ 41.983555][ T8227] platform LNRO0005:1c: shutdown
[ 41.984454][ T8227] platform LNRO0005:1b: shutdown
[ 41.985523][ T8227] platform LNRO0005:1a: shutdown
[ 41.986416][ T8227] platform LNRO0005:19: shutdown
[ 41.987310][ T8227] platform LNRO0005:18: shutdown
[ 41.988205][ T8227] platform LNRO0005:17: shutdown
[ 41.989159][ T8227] platform LNRO0005:16: shutdown
[ 41.990059][ T8227] platform LNRO0005:15: shutdown
[ 41.990956][ T8227] platform LNRO0005:14: shutdown
[ 41.991848][ T8227] platform LNRO0005:13: shutdown
[ 41.992753][ T8227] platform LNRO0005:12: shutdown
[ 41.993638][ T8227] platform LNRO0005:11: shutdown
[ 41.994517][ T8227] platform LNRO0005:10: shutdown
[ 41.995396][ T8227] platform LNRO0005:0f: shutdown
[ 41.996266][ T8227] platform LNRO0005:0e: shutdown
[ 41.997135][ T8227] platform LNRO0005:0d: shutdown
[ 41.998002][ T8227] platform LNRO0005:0c: shutdown
[ 41.998901][ T8227] platform LNRO0005:0b: shutdown
[ 41.999766][ T8227] platform LNRO0005:0a: shutdown
[ 42.000629][ T8227] platform LNRO0005:09: shutdown
[ 42.001490][ T8227] platform LNRO0005:08: shutdown
[ 42.002351][ T8227] platform LNRO0005:07: shutdown
[ 42.003224][ T8227] platform LNRO0005:06: shutdown
[ 42.004087][ T8227] platform LNRO0005:05: shutdown
[ 42.004950][ T8227] platform LNRO0005:04: shutdown
[ 42.005812][ T8227] platform LNRO0005:03: shutdown
[ 42.006675][ T8227] platform LNRO0005:02: shutdown
[ 42.007537][ T8227] platform LNRO0005:01: shutdown
[ 42.008401][ T8227] platform LNRO0005:00: shutdown
[ 42.009320][ T8227] fw_cfg QEMU0002:00: shutdown
[ 42.010159][ T8227] sbsa-uart ARMH0011:00: shutdown
[ 42.011097][ T8227] reg-dummy reg-dummy: shutdown
[ 42.012042][ T8227] kexec_core: Starting new kernel
[ 42.252819][ T10] psci: CPU1 killed (polled 0 ms)
[ 42.352823][ T304] psci: CPU2 killed (polled 0 ms)
[ 42.442807][ T304] psci: CPU3 killed (polled 0 ms)
[ 42.532842][ T304] psci: CPU4 killed (polled 0 ms)
[ 42.652807][ T304] psci: CPU5 killed (polled 0 ms)
[ 42.759163][ T304] psci: CPU6 killed (polled 0 ms)
[ 42.839104][ T304] psci: CPU7 killed (polled 0 ms)

>
> Thanks,
> Ming
>
>