Re: WARNING: at drivers/tty/tty_buffer.c:476 flush_to_ldisc()

[Fengguang Wu <fengguang.wu@intel.com>]

Hi Jiri,

On Tue, Nov 13, 2012 at 08:55:34PM +0100, Jiri Slaby wrote:
> On 11/13/2012 06:20 AM, Fengguang Wu wrote:
> > Hi Jiri,
> 
> Hi,
> 
> > I got the following warning
> > 
> > cat: /proc/1/maps: No such file or directory
> > [   72.249806] ------------[ cut here ]------------
> > [   72.250807] WARNING: at /c/kernel-tests/src/tip/drivers/tty/tty_buffer.c:476 flush_to_ldisc+0x5a/0x1ad()
> > [   72.252674] tty is NULL
> > [   72.253182] Pid: 15, comm: kworker/0:1 Not tainted 3.7.0-rc4-05821-gdb38463 #166
> > [   72.253672] Call Trace:
> > [   72.253672]  [<ffffffff8103ccee>] warn_slowpath_common+0x62/0x79
> > [   72.256297]  [<ffffffff8103cd73>] warn_slowpath_fmt+0x46/0x48
> > [   72.257292]  [<ffffffff811e66c3>] flush_to_ldisc+0x5a/0x1ad
> > [   72.258478]  [<ffffffff81053a6d>] process_one_work+0x246/0x44f
> > [   72.259640]  [<ffffffff810539da>] ? process_one_work+0x1b3/0x44f
> > [   72.260817]  [<ffffffff811e6669>] ? tty_buffer_free+0x61/0x61
> > [   72.261820]  [<ffffffff81053fd2>] worker_thread+0x1ed/0x2c8
> > [   72.262883]  [<ffffffff81053de5>] ? rescuer_thread+0x140/0x140
> > [   72.263878]  [<ffffffff81058556>] kthread+0xd4/0xdc
> > [   72.264980]  [<ffffffff810625d7>] ? finish_task_switch.constprop.79+0x7a/0xbf
> > [   72.266150]  [<ffffffff81058482>] ? __kthread_parkme+0x61/0x61
> > [   72.267145]  [<ffffffff81533bea>] ret_from_fork+0x7a/0xb0
> > [   72.268361]  [<ffffffff81058482>] ? __kthread_parkme+0x61/0x61
> > 
> > and it's bisected to
> > 
> > commit ecbbfd44a08fa80e0d664814efd4c187721b85f6
> 
> Yes, I know about this already. Can you reproducible that easily given
> you bisected that? I would love to be able to reproduce that...

I checked the bisect log (attached in the original email) and it shows
that it may take several hundreds of boots to reproduce the error once.
So in the bisect, it regards 7540 repeated good boots as one success.

Thanks,
Fengguang