Re: WARNING: at drivers/tty/tty_ldisc.c:766 tty_ldisc_reinit+0x7d/0x90()

From: Arnd Bergmann
Date: Tue Jul 19 2011 - 13:54:11 EST


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
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