System hang from holding left shift key

System hang from holding left shift key

[Larry Finger]

While absentmindedly holding down the left shift key as I was thinking about my
next input, I froze the keyboard. After 3 seconds, the system sounded a high
beep, and then a low beep after another 3 seconds. At that point, no key entry
had any effect. From the beeps, one might conclude that the input buffer is
full, but a CTRL/U did not clear it. Fortunately, a short press on the power
button shut down the machine cleanly.

I don't know if this is a regression. I found it in v2.6.28-rc2, but the oldest
kernel that I could test (v2.6.24) already has the problem.

When the beeps occur, a stack dump is as follows:

Pid: 2989, comm: Xorg Not tainted 2.6.28-rc2-Linus-00473-g67d1128-dirty #2
Call Trace:
  [<ffffffff803957ce>] kd_mksound+0x69/0xa9
  [<ffffffff8039196c>] vt_ioctl+0x3c4/0x1744
  [<ffffffff8038b097>] tty_ioctl+0x793/0x7fa
  [<ffffffff8025c6c0>] ? trace_hardirqs_off+0xd/0xf
  [<ffffffff8044f94a>] ? _spin_unlock_irqrestore+0x3d/0x4c
  [<ffffffff802bf102>] vfs_ioctl+0x2f/0x7d
  [<ffffffff802bf4fe>] do_vfs_ioctl+0x3ae/0x3e0
  [<ffffffff8020c07c>] ? sysret_check+0x27/0x62
  [<ffffffff802bf577>] sys_ioctl+0x47/0x6a
  [<ffffffff8020c04b>] system_call_fastpath+0x16/0x1b

Thanks,

Larry

Re: System hang from holding left shift key

[Andi Kleen]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> While absentmindedly holding down the left shift key as I was thinking about my
> next input, I froze the keyboard. After 3 seconds, the system sounded a high
> beep, and then a low beep after another 3 seconds. At that point, no key entry
> had any effect. From the beeps, one might conclude that the input buffer is
> full, but a CTRL/U did not clear it. Fortunately, a short press on the power
> button shut down the machine cleanly.
> 
> I don't know if this is a regression. I found it in v2.6.28-rc2, but the oldest
> kernel that I could test (v2.6.24) already has the problem.

I vaguely remember hitting something like that long ago (much earlier
2.6). But i wasn't able to stabilize it so I never reported it or
tried to track it down. But it's probably not a new problem.

-Andi


-- 
ak@linux.intel.com

Re: System hang from holding left shift key

[Pavel Machek]

> While absentmindedly holding down the left shift key as I was thinking about my
> next input, I froze the keyboard. After 3 seconds, the system sounded a high
> beep, and then a low beep after another 3 seconds. At that point, no key entry
> had any effect. From the beeps, one might conclude that the input buffer is
> full, but a CTRL/U did not clear it. Fortunately, a short press on the power
> button shut down the machine cleanly.
> 
> I don't know if this is a regression. I found it in v2.6.28-rc2, but the oldest
> kernel that I could test (v2.6.24) already has the problem.
> 
> When the beeps occur, a stack dump is as follows:

What kind of machine is that...? I can't reproduce it here, do I need
some accessibility options enabled?

									Pavel


> Pid: 2989, comm: Xorg Not tainted 2.6.28-rc2-Linus-00473-g67d1128-dirty #2
> Call Trace:
>   [<ffffffff803957ce>] kd_mksound+0x69/0xa9
>   [<ffffffff8039196c>] vt_ioctl+0x3c4/0x1744
>   [<ffffffff8038b097>] tty_ioctl+0x793/0x7fa
>   [<ffffffff8025c6c0>] ? trace_hardirqs_off+0xd/0xf
>   [<ffffffff8044f94a>] ? _spin_unlock_irqrestore+0x3d/0x4c
>   [<ffffffff802bf102>] vfs_ioctl+0x2f/0x7d
>   [<ffffffff802bf4fe>] do_vfs_ioctl+0x3ae/0x3e0
>   [<ffffffff8020c07c>] ? sysret_check+0x27/0x62
>   [<ffffffff802bf577>] sys_ioctl+0x47/0x6a
>   [<ffffffff8020c04b>] system_call_fastpath+0x16/0x1b
> 
> Thanks,
> 
> Larry
> 
> 
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Re: System hang from holding left shift key

[Larry Finger]

Pavel Machek wrote:
>> While absentmindedly holding down the left shift key as I was thinking about my
>> next input, I froze the keyboard. After 3 seconds, the system sounded a high
>> beep, and then a low beep after another 3 seconds. At that point, no key entry
>> had any effect. From the beeps, one might conclude that the input buffer is
>> full, but a CTRL/U did not clear it. Fortunately, a short press on the power
>> button shut down the machine cleanly.
>>
>> I don't know if this is a regression. I found it in v2.6.28-rc2, but the oldest
>> kernel that I could test (v2.6.24) already has the problem.
>>
>> When the beeps occur, a stack dump is as follows:
> 
> What kind of machine is that...? I can't reproduce it here, do I need
> some accessibility options enabled?

It is an HP dv2815nr notebook with an Turion X2 CPU running the x86_64 version
of openSUSE 11.0.

I'm not running any special options that I know about. The only strange thing is
that the shift keys autorepeat.

Larry