Bug 16248

Yet another qemu boot failure:

Central error: [   22.672275] xhci_hcd 0000:00:04.0: Error while assigning device slot ID: Command Ring Stopped
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[    0.842084] Run /sbin/init as init process
[    0.842175]   with arguments:
[    0.842176]     /sbin/init
[    0.842177]   with environment:
[    0.842178]     HOME=/
[    0.842178]     TERM=linux
[   21.889260] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[   21.891833] rcu:     3-...0: (1 GPs behind) idle=0b84/1/0x4000000000000000 softirq=29/30 fqs=2559
[   21.894388] rcu:     (detected by 0, t=5252 jiffies, g=-1143, q=194 ncpus=4)
[   21.896416] Sending NMI from CPU 0 to CPUs 3:
[   22.672275] xhci_hcd 0000:00:04.0: Error while assigning device slot ID: Command Ring Stopped
[   22.673006] xhci_hcd 0000:00:04.0: Max number of devices this xHCI host supports is 64.
[   22.673364] usb usb1-port1: couldn't allocate usb_device
[   31.904741] rcu: rcu_preempt kthread starved for 2494 jiffies! g-1143 f0x0 RCU_GP_DOING_FQS(6) ->state=0x0 ->cpu=2
[   31.904745] NMI backtrace for cpu 3
[   31.904754] CPU: 3 UID: 0 PID: 106 Comm: S04udev Not tainted 6.18.19-yocto-standard #1 PREEMPT 
[   31.904757] Hardware name: linux,dummy-virt (DT)
[   31.904758] pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   31.904760] pc : handle_softirqs+0xa4/0x360
[   31.904765] lr : __do_softirq+0x1c/0x28
[   31.904767] sp : ffff800081703f30

***********************
Central error: [   31.923156] xhci_hcd 0000:00:04.0: Error while assigning device slot ID: Command Ring Stopped
***********************
[   31.904809]  copy_page+0x48/0xc0 (P)
[   31.904811]  copy_user_highpage+0x1c/0x40
[   31.904813]  do_wp_page+0x258/0xb40
[   31.904816]  __handle_mm_fault+0x538/0xc90
[   31.904819]  handle_mm_fault+0x98/0x2b0
[   31.904821]  do_page_fault+0x154/0x768
[   31.904823]  do_mem_abort+0x48/0xa0
[   31.904825]  el0_da+0x2c/0x88
[   31.904827]  el0t_64_sync_handler+0xd0/0xe8
[   31.904829]  el0t_64_sync+0x198/0x1a0
[   31.923156] xhci_hcd 0000:00:04.0: Error while assigning device slot ID: Command Ring Stopped
[   31.923288] rcu:     Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
[   31.927451] xhci_hcd 0000:00:04.0: Max number of devices this xHCI host supports is 64.
[   31.927515] rcu: RCU grace-period kthread stack dump:
[   31.931193] usb usb1-port2: couldn't allocate usb_device
[   31.931243] task:rcu_preempt     state:I stack:0     pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00000010
[   31.940533] Call trace:
[   31.940889]  __switch_to+0xf0/0x1c8 (T)
[   31.941427]  __schedule+0x35c/0xb10
[   31.941937]  schedule+0x3c/0x120
[   31.942330]  schedule_timeout+0x88/0x128