On Tuesday 19 July 2011 13:33:36 Vegard Nossum wrote:

> [   74.930391]  [<c15e9879>] ? printk+0x18/0x1a
> [   74.931650]  [<c103e128>] warn_slowpath_common+0x68/0xa0
> [   74.933367]  [<c128515d>] ? tty_ldisc_reinit+0x7d/0x90
> [   74.934907]  [<c128515d>] ? tty_ldisc_reinit+0x7d/0x90
> [   74.936242]  [<c103e1fd>] warn_slowpath_null+0x1d/0x20
> [   74.937584]  [<c128515d>] tty_ldisc_reinit+0x7d/0x90
> [   74.939152]  [<c128577f>] tty_ldisc_hangup+0xdf/0x200
> [   74.968743]  [<c127e4f5>] __tty_hangup+0xe5/0x360
> [   74.970158]  [<c127ff3c>] disassociate_ctty+0x6c/0x200
> [   74.971526]  [<c104198b>] do_exit+0x55b/0x7d0
> [   74.972745]  [<c127dd20>] ? tty_write_lock+0x50/0x50
> [   74.974052]  [<c1041c79>] do_group_exit+0x39/0xa0
> [   74.975338]  [<c1041cf3>] sys_exit_group+0x13/0x20
> [   74.976658]  [<c15ec85c>] sysenter_do_call+0x12/0x2c
> [   74.977938]  [<c15e0000>] ? pci_fixup_i450gx+0x40/0x53
> [   74.979462] ---[ end trace c3cfae8b1239077b ]---
> 
> This is inside qemu/kvm with usb pass-through: -usbdevice host:9ac4:4b8f
> 
> Any ideas?

This is the WARN_ON that Jiri added in 92f6fa09b "TTY: ldisc, do not close
until there are readers".

Is the login process that triggered this running on the USB device you pass
through, or do you have vga or serial console?

	Arnd