Re: INFO: possible recursive locking detected ps2_command

Re: INFO: possible recursive locking detected ps2_command

[Andrew Morton]

(cc linux-input)

On Thu, 31 Jul 2008 11:41:25 +0200
"Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:

> Hi
> 
> During mouse unplugging from psaux connector from the laptops' docking
> station I've got attached INFO trace.
> (laptops still has synaptics device)
> 
> Also for unknown reason to me  psaux mouse & synaptic device do not
> work somehow together - is it hw limitation
> of /dev/input/mice  interface?
> (USB mouse and synaptics do work quite well together)
> 
> [ INFO: possible recursive locking detected ]
> 2.6.27-rc1 #48

(it's 2.6.27-rc1)

> ---------------------------------------------
> kseriod/166 is trying to acquire lock:
>  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> 
> but task is already holding lock:
>  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> 
> other info that might help us debug this:
> 4 locks held by kseriod/166:
>  #0:  (serio_mutex){--..}, at: [<ffffffff8126cc1e>] serio_thread+0x3e/0x410
>  #1:  (&serio->drv_mutex){--..}, at: [<ffffffff8126bf8b>]
> serio_connect_driver+0x2b/0x50
>  #2:  (psmouse_mutex){--..}, at: [<ffffffffa009aa00>]
> psmouse_connect+0x30/0x2c0 [psmouse]
>  #3:  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>]
> ps2_command+0x5e/0x460
> 
> stack backtrace:
> Pid: 166, comm: kseriod Not tainted 2.6.27-rc1 #48
> 
> Call Trace:
>  [<ffffffff81068bda>] __lock_acquire+0xcea/0x13b0
>  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
>  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
>  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
>  [<ffffffff81069336>] lock_acquire+0x96/0xe0
>  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
>  [<ffffffff81313861>] mutex_lock_nested+0xc1/0x340
>  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
>  [<ffffffff810135a0>] ? native_sched_clock+0x90/0xb0
>  [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
>  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
>  [<ffffffff81065834>] ? get_lock_stats+0x34/0x70
>  [<ffffffffa009977d>] psmouse_sliced_command+0x2d/0x90 [psmouse]
>  [<ffffffff8126e838>] ? ps2_sendbyte+0x48/0x130
>  [<ffffffffa009b8f7>] synaptics_pt_write+0x27/0x60 [psmouse]
>  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
>  [<ffffffff8126e84d>] ps2_sendbyte+0x5d/0x130
>  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
>  [<ffffffff8126ea4d>] ps2_command+0xfd/0x460
>  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
>  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
>  [<ffffffffa0099917>] psmouse_probe+0x27/0xa0 [psmouse]
>  [<ffffffff8126c1e1>] ? serio_open+0x11/0x50
>  [<ffffffffa009ab48>] psmouse_connect+0x178/0x2c0 [psmouse]
>  [<ffffffff8126bf96>] serio_connect_driver+0x36/0x50
>  [<ffffffff8126bfcb>] serio_driver_probe+0x1b/0x20
>  [<ffffffff81221112>] driver_probe_device+0xa2/0x1e0
>  [<ffffffff812212e0>] ? __device_attach+0x0/0x10
>  [<ffffffff812212e9>] __device_attach+0x9/0x10
>  [<ffffffff8122050b>] bus_for_each_drv+0x6b/0xa0
>  [<ffffffff812213b8>] device_attach+0x88/0x90
>  [<ffffffff812202d5>] bus_attach_device+0x55/0x80
>  [<ffffffff8121ee99>] device_add+0x4f9/0x610
>  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
>  [<ffffffff8126ce1c>] serio_thread+0x23c/0x410
>  [<ffffffff810571a0>] ? autoremove_wake_function+0x0/0x40
>  [<ffffffff8126cbe0>] ? serio_thread+0x0/0x410
>  [<ffffffff81056de9>] kthread+0x49/0x90
>  [<ffffffff8100d669>] child_rip+0xa/0x11
>  [<ffffffff8103b757>] ? finish_task_switch+0x57/0x110
>  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
>  [<ffffffff8100cc73>] ? restore_args+0x0/0x30
>  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
>  [<ffffffff81056da0>] ? kthread+0x0/0x90
>  [<ffffffff8100d65f>] ? child_rip+0x0/0x11

Re: INFO: possible recursive locking detected ps2_command

[Dmitry Torokhov]

On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
> 
> (cc linux-input)
> 
> On Thu, 31 Jul 2008 11:41:25 +0200
> "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
> 
> > Hi
> > 
> > During mouse unplugging from psaux connector from the laptops' docking
> > station I've got attached INFO trace.
> > (laptops still has synaptics device)
> > 

Dell?

> > Also for unknown reason to me  psaux mouse & synaptic device do not
> > work somehow together - is it hw limitation
> > of /dev/input/mice  interface?
> > (USB mouse and synaptics do work quite well together)
> > 
> > [ INFO: possible recursive locking detected ]
> > 2.6.27-rc1 #48
> 
> (it's 2.6.27-rc1)
> 

Peter, here is the trace we talked about long time ago. For some reason
lockdep annotation only works once. If reconnect is forced or psmouse
module is reloaded lockdep starts complaining about passthrough port.

> > ---------------------------------------------
> > kseriod/166 is trying to acquire lock:
> >  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> > 
> > but task is already holding lock:
> >  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> > 
> > other info that might help us debug this:
> > 4 locks held by kseriod/166:
> >  #0:  (serio_mutex){--..}, at: [<ffffffff8126cc1e>] serio_thread+0x3e/0x410
> >  #1:  (&serio->drv_mutex){--..}, at: [<ffffffff8126bf8b>]
> > serio_connect_driver+0x2b/0x50
> >  #2:  (psmouse_mutex){--..}, at: [<ffffffffa009aa00>]
> > psmouse_connect+0x30/0x2c0 [psmouse]
> >  #3:  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>]
> > ps2_command+0x5e/0x460
> > 
> > stack backtrace:
> > Pid: 166, comm: kseriod Not tainted 2.6.27-rc1 #48
> > 
> > Call Trace:
> >  [<ffffffff81068bda>] __lock_acquire+0xcea/0x13b0
> >  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
> >  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
> >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> >  [<ffffffff81069336>] lock_acquire+0x96/0xe0
> >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> >  [<ffffffff81313861>] mutex_lock_nested+0xc1/0x340
> >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> >  [<ffffffff810135a0>] ? native_sched_clock+0x90/0xb0
> >  [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> >  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
> >  [<ffffffff81065834>] ? get_lock_stats+0x34/0x70
> >  [<ffffffffa009977d>] psmouse_sliced_command+0x2d/0x90 [psmouse]
> >  [<ffffffff8126e838>] ? ps2_sendbyte+0x48/0x130
> >  [<ffffffffa009b8f7>] synaptics_pt_write+0x27/0x60 [psmouse]
> >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> >  [<ffffffff8126e84d>] ps2_sendbyte+0x5d/0x130
> >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> >  [<ffffffff8126ea4d>] ps2_command+0xfd/0x460
> >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> >  [<ffffffffa0099917>] psmouse_probe+0x27/0xa0 [psmouse]
> >  [<ffffffff8126c1e1>] ? serio_open+0x11/0x50
> >  [<ffffffffa009ab48>] psmouse_connect+0x178/0x2c0 [psmouse]
> >  [<ffffffff8126bf96>] serio_connect_driver+0x36/0x50
> >  [<ffffffff8126bfcb>] serio_driver_probe+0x1b/0x20
> >  [<ffffffff81221112>] driver_probe_device+0xa2/0x1e0
> >  [<ffffffff812212e0>] ? __device_attach+0x0/0x10
> >  [<ffffffff812212e9>] __device_attach+0x9/0x10
> >  [<ffffffff8122050b>] bus_for_each_drv+0x6b/0xa0
> >  [<ffffffff812213b8>] device_attach+0x88/0x90
> >  [<ffffffff812202d5>] bus_attach_device+0x55/0x80
> >  [<ffffffff8121ee99>] device_add+0x4f9/0x610
> >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> >  [<ffffffff8126ce1c>] serio_thread+0x23c/0x410
> >  [<ffffffff810571a0>] ? autoremove_wake_function+0x0/0x40
> >  [<ffffffff8126cbe0>] ? serio_thread+0x0/0x410
> >  [<ffffffff81056de9>] kthread+0x49/0x90
> >  [<ffffffff8100d669>] child_rip+0xa/0x11
> >  [<ffffffff8103b757>] ? finish_task_switch+0x57/0x110
> >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> >  [<ffffffff8100cc73>] ? restore_args+0x0/0x30
> >  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
> >  [<ffffffff81056da0>] ? kthread+0x0/0x90
> >  [<ffffffff8100d65f>] ? child_rip+0x0/0x11
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-input" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Dmitry

Re: INFO: possible recursive locking detected ps2_command

[Peter Zijlstra]

On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote:
> On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
> > 
> > (cc linux-input)
> > 
> > On Thu, 31 Jul 2008 11:41:25 +0200
> > "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
> > 
> > > Hi
> > > 
> > > During mouse unplugging from psaux connector from the laptops' docking
> > > station I've got attached INFO trace.
> > > (laptops still has synaptics device)
> > > 
> 
> Dell?
> 
> > > Also for unknown reason to me  psaux mouse & synaptic device do not
> > > work somehow together - is it hw limitation
> > > of /dev/input/mice  interface?
> > > (USB mouse and synaptics do work quite well together)
> > > 
> > > [ INFO: possible recursive locking detected ]
> > > 2.6.27-rc1 #48
> > 
> > (it's 2.6.27-rc1)
> > 
> 
> Peter, here is the trace we talked about long time ago. For some reason
> lockdep annotation only works once. If reconnect is forced or psmouse
> module is reloaded lockdep starts complaining about passthrough port.

Bit puzzling - and I don't have any ps2 hardware around to test with
(nor do I normally use modules - but that is fixable of course).

Does Rabin's patch help?

  http://lkml.org/lkml/2008/8/7/329

> > > ---------------------------------------------
> > > kseriod/166 is trying to acquire lock:
> > >  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> > > 
> > > but task is already holding lock:
> > >  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> > > 
> > > other info that might help us debug this:
> > > 4 locks held by kseriod/166:
> > >  #0:  (serio_mutex){--..}, at: [<ffffffff8126cc1e>] serio_thread+0x3e/0x410
> > >  #1:  (&serio->drv_mutex){--..}, at: [<ffffffff8126bf8b>]
> > > serio_connect_driver+0x2b/0x50
> > >  #2:  (psmouse_mutex){--..}, at: [<ffffffffa009aa00>]
> > > psmouse_connect+0x30/0x2c0 [psmouse]
> > >  #3:  (&ps2dev->cmd_mutex){--..}, at: [<ffffffff8126e9ae>]
> > > ps2_command+0x5e/0x460
> > > 
> > > stack backtrace:
> > > Pid: 166, comm: kseriod Not tainted 2.6.27-rc1 #48
> > > 
> > > Call Trace:
> > >  [<ffffffff81068bda>] __lock_acquire+0xcea/0x13b0
> > >  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
> > >  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
> > >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> > >  [<ffffffff81069336>] lock_acquire+0x96/0xe0
> > >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> > >  [<ffffffff81313861>] mutex_lock_nested+0xc1/0x340
> > >  [<ffffffff8126e9ae>] ? ps2_command+0x5e/0x460
> > >  [<ffffffff810135a0>] ? native_sched_clock+0x90/0xb0
> > >  [<ffffffff8126e9ae>] ps2_command+0x5e/0x460
> > >  [<ffffffff81066401>] ? trace_hardirqs_off_caller+0x21/0xc0
> > >  [<ffffffff81065834>] ? get_lock_stats+0x34/0x70
> > >  [<ffffffffa009977d>] psmouse_sliced_command+0x2d/0x90 [psmouse]
> > >  [<ffffffff8126e838>] ? ps2_sendbyte+0x48/0x130
> > >  [<ffffffffa009b8f7>] synaptics_pt_write+0x27/0x60 [psmouse]
> > >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> > >  [<ffffffff8126e84d>] ps2_sendbyte+0x5d/0x130
> > >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> > >  [<ffffffff8126ea4d>] ps2_command+0xfd/0x460
> > >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> > >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> > >  [<ffffffffa0099917>] psmouse_probe+0x27/0xa0 [psmouse]
> > >  [<ffffffff8126c1e1>] ? serio_open+0x11/0x50
> > >  [<ffffffffa009ab48>] psmouse_connect+0x178/0x2c0 [psmouse]
> > >  [<ffffffff8126bf96>] serio_connect_driver+0x36/0x50
> > >  [<ffffffff8126bfcb>] serio_driver_probe+0x1b/0x20
> > >  [<ffffffff81221112>] driver_probe_device+0xa2/0x1e0
> > >  [<ffffffff812212e0>] ? __device_attach+0x0/0x10
> > >  [<ffffffff812212e9>] __device_attach+0x9/0x10
> > >  [<ffffffff8122050b>] bus_for_each_drv+0x6b/0xa0
> > >  [<ffffffff812213b8>] device_attach+0x88/0x90
> > >  [<ffffffff812202d5>] bus_attach_device+0x55/0x80
> > >  [<ffffffff8121ee99>] device_add+0x4f9/0x610
> > >  [<ffffffff81319840>] ? sub_preempt_count+0x80/0x120
> > >  [<ffffffff8126ce1c>] serio_thread+0x23c/0x410
> > >  [<ffffffff810571a0>] ? autoremove_wake_function+0x0/0x40
> > >  [<ffffffff8126cbe0>] ? serio_thread+0x0/0x410
> > >  [<ffffffff81056de9>] kthread+0x49/0x90
> > >  [<ffffffff8100d669>] child_rip+0xa/0x11
> > >  [<ffffffff8103b757>] ? finish_task_switch+0x57/0x110
> > >  [<ffffffff81315acd>] ? _spin_unlock_irq+0x3d/0x80
> > >  [<ffffffff8100cc73>] ? restore_args+0x0/0x30
> > >  [<ffffffff810664ad>] ? trace_hardirqs_off+0xd/0x10
> > >  [<ffffffff81056da0>] ? kthread+0x0/0x90
> > >  [<ffffffff8100d65f>] ? child_rip+0x0/0x11

Re: INFO: possible recursive locking detected ps2_command

[Dmitry Torokhov]

On Fri, Aug 08, 2008 at 12:49:49PM +0200, Peter Zijlstra wrote:
> On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote:
> > On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
> > > 
> > > (cc linux-input)
> > > 
> > > On Thu, 31 Jul 2008 11:41:25 +0200
> > > "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
> > > 
> > > > Hi
> > > > 
> > > > During mouse unplugging from psaux connector from the laptops' docking
> > > > station I've got attached INFO trace.
> > > > (laptops still has synaptics device)
> > > > 
> > 
> > Dell?
> > 
> > > > Also for unknown reason to me  psaux mouse & synaptic device do not
> > > > work somehow together - is it hw limitation
> > > > of /dev/input/mice  interface?
> > > > (USB mouse and synaptics do work quite well together)
> > > > 
> > > > [ INFO: possible recursive locking detected ]
> > > > 2.6.27-rc1 #48
> > > 
> > > (it's 2.6.27-rc1)
> > > 
> > 
> > Peter, here is the trace we talked about long time ago. For some reason
> > lockdep annotation only works once. If reconnect is forced or psmouse
> > module is reloaded lockdep starts complaining about passthrough port.
> 
> Bit puzzling - and I don't have any ps2 hardware around to test with
> (nor do I normally use modules - but that is fixable of course).
> 
> Does Rabin's patch help?
> 
>   http://lkml.org/lkml/2008/8/7/329
> 

I doubt it resolves problem fully because it only takes care of module
unload. I can easily trip lockdep by reconnecting the device. Just to
give some more details about the problem:

 - synaptics touchpads have a pass-through port that allows to connect
   either external mouse or maybe a trackpoint device. Both devices
   are represented by 'serio' structures and are handled by the same
   driver (psmouse).

 - as far as I know we have proper locking there and lockdep
   annotatinos were added to lockdep to reflect the nesting of the
   serio ports.

 - if child port (pass-through port) is destroyed and recreated (due
   to module unload, or because user requested reconnect through sysfs
   or system-initiated reconnect) lockdep starts complaining although
   the new child port should still have the same "depth" as the old
   one.

Thanks!

-- 
Dmitry

Re: INFO: possible recursive locking detected ps2_command

[Zdenek Kabelac]

2008/8/8 Dmitry Torokhov <dmitry.torokhov@gmail.com>:
> On Fri, Aug 08, 2008 at 12:49:49PM +0200, Peter Zijlstra wrote:
>> On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote:
>> > On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
>> > >
>> > > (cc linux-input)
>> > >
>> > > On Thu, 31 Jul 2008 11:41:25 +0200
>> > > "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
>> > >
>> > > > Hi
>> > > >
>> > > > During mouse unplugging from psaux connector from the laptops' docking
>> > > > station I've got attached INFO trace.
>> > > > (laptops still has synaptics device)
>> > > >
>> >
>> > Dell?
>> >
>> > > > Also for unknown reason to me  psaux mouse & synaptic device do not
>> > > > work somehow together - is it hw limitation
>> > > > of /dev/input/mice  interface?
>> > > > (USB mouse and synaptics do work quite well together)
>> > > >
>> > > > [ INFO: possible recursive locking detected ]
>> > > > 2.6.27-rc1 #48
>> > >
>> > > (it's 2.6.27-rc1)
>> > >
>> >
>> > Peter, here is the trace we talked about long time ago. For some reason
>> > lockdep annotation only works once. If reconnect is forced or psmouse
>> > module is reloaded lockdep starts complaining about passthrough port.
>>
>> Bit puzzling - and I don't have any ps2 hardware around to test with
>> (nor do I normally use modules - but that is fixable of course).
>>
>> Does Rabin's patch help?
>>
>>   http://lkml.org/lkml/2008/8/7/329
>>
>
> I doubt it resolves problem fully because it only takes care of module
> unload. I can easily trip lockdep by reconnecting the device. Just to
> give some more details about the problem:
>
>  - synaptics touchpads have a pass-through port that allows to connect
>   either external mouse or maybe a trackpoint device. Both devices
>   are represented by 'serio' structures and are handled by the same
>   driver (psmouse).
>
>  - as far as I know we have proper locking there and lockdep
>   annotatinos were added to lockdep to reflect the nesting of the
>   serio ports.
>
>  - if child port (pass-through port) is destroyed and recreated (due
>   to module unload, or because user requested reconnect through sysfs
>   or system-initiated reconnect) lockdep starts complaining although
>   the new child port should still have the same "depth" as the old
>   one.
>

Well just noticed this issue again in my log - during resume operation
- thus no external mouse connection in the game this time:

platform dock.2: completing resume
platform dock.1: completing resume
platform dock.0: completing resume
PM: Finishing wakeup.
Restarting tasks ... done.
PM: Removing info for No Bus:vcs63
PM: Removing info for No Bus:vcsa63
psmouse.c: Failed to enable mouse on isa0060/serio1
PM: Removing info for No Bus:mouse1
PM: Removing info for No Bus:event8
PM: Removing info for No Bus:input8

=============================================
[ INFO: possible recursive locking detected ]
2.6.31-rc8-00043-gf2332bf #30
---------------------------------------------
kseriod/207 is trying to acquire lock:
 (&ps2dev->cmd_mutex){+.+...}, at: [<ffffffff8132675b>] ps2_command+0x5b/0x470

but task is already holding lock:
 (&ps2dev->cmd_mutex){+.+...}, at: [<ffffffff8132675b>] ps2_command+0x5b/0x470

other info that might help us debug this:
4 locks held by kseriod/207:
 #0:  (serio_mutex){+.+.+.}, at: [<ffffffff8132453e>] serio_thread+0x3e/0x400
 #1:  (&serio->drv_mutex){+.+.+.}, at: [<ffffffff81323b00>]
serio_connect_driver+0x30/0x60
 #2:  (psmouse_mutex){+.+.+.}, at: [<ffffffffa00c5f85>]
psmouse_connect+0x35/0x370 [psmouse]
 #3:  (&ps2dev->cmd_mutex){+.+...}, at: [<ffffffff8132675b>]
ps2_command+0x5b/0x470

stack backtrace:
Pid: 207, comm: kseriod Not tainted 2.6.31-rc8-00043-gf2332bf #30
Call Trace:
 [<ffffffff8107f0ba>] __lock_acquire+0xe6a/0x1090
 [<ffffffff8107f37a>] lock_acquire+0x9a/0x180
 [<ffffffff8132675b>] ? ps2_command+0x5b/0x470
 [<ffffffff813da81f>] __mutex_lock_common+0x5f/0x4a0
 [<ffffffff8132675b>] ? ps2_command+0x5b/0x470
 [<ffffffff8100f4b8>] ? dump_trace+0x118/0x2f0
 [<ffffffff8132675b>] ? ps2_command+0x5b/0x470
 [<ffffffff813dad41>] mutex_lock_nested+0x41/0x50
 [<ffffffff8132675b>] ps2_command+0x5b/0x470
 [<ffffffffa00c47b3>] psmouse_sliced_command+0x33/0x90 [psmouse]
 [<ffffffffa00c6a9c>] synaptics_pt_write+0x2c/0x60 [psmouse]
 [<ffffffff81326636>] ps2_sendbyte+0x66/0x130
 [<ffffffff8107d7ed>] ? trace_hardirqs_on_caller+0x15d/0x1a0
 [<ffffffff8107d83d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff813267f9>] ps2_command+0xf9/0x470
 [<ffffffff8107d83d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff813dcbbb>] ? _spin_unlock_irq+0x3b/0x60
 [<ffffffffa00c494c>] psmouse_probe+0x2c/0xa0 [psmouse]
 [<ffffffff81323d86>] ? serio_open+0x16/0x50
 [<ffffffffa00c6108>] psmouse_connect+0x1b8/0x370 [psmouse]
 [<ffffffff81323b0b>] serio_connect_driver+0x3b/0x60
 [<ffffffff81323b50>] serio_driver_probe+0x20/0x30
 [<ffffffff812d2379>] driver_probe_device+0x89/0x180
 [<ffffffff812d2520>] ? __device_attach+0x0/0x60
 [<ffffffff812d2573>] __device_attach+0x53/0x60
 [<ffffffff812d13dc>] bus_for_each_drv+0x6c/0xa0
 [<ffffffff812d2639>] device_attach+0x89/0x90
 [<ffffffff81323cbd>] serio_find_driver+0x1d/0x50
 [<ffffffff813240c7>] serio_reconnect_port+0x57/0x90
 [<ffffffff81324758>] serio_thread+0x258/0x400
 [<ffffffff81069540>] ? autoremove_wake_function+0x0/0x40
 [<ffffffff81324500>] ? serio_thread+0x0/0x400
 [<ffffffff810690e6>] kthread+0xa6/0xb0
 [<ffffffff8100d2da>] child_rip+0xa/0x20
 [<ffffffff8100cc40>] ? restore_args+0x0/0x30
 [<ffffffff81069040>] ? kthread+0x0/0xb0
 [<ffffffff8100d2d0>] ? child_rip+0x0/0x20

Re: INFO: possible recursive locking detected ps2_command

[Dmitry Torokhov]

On Fri, Sep 04, 2009 at 12:48:45AM +0200, Zdenek Kabelac wrote:
> 2008/8/8 Dmitry Torokhov <dmitry.torokhov@gmail.com>:
> > On Fri, Aug 08, 2008 at 12:49:49PM +0200, Peter Zijlstra wrote:
> >> On Thu, 2008-07-31 at 23:04 -0400, Dmitry Torokhov wrote:
> >> > On Thu, Jul 31, 2008 at 02:57:39PM -0700, Andrew Morton wrote:
> >> > >
> >> > > (cc linux-input)
> >> > >
> >> > > On Thu, 31 Jul 2008 11:41:25 +0200
> >> > > "Zdenek Kabelac" <zdenek.kabelac@gmail.com> wrote:
> >> > >
> >> > > > Hi
> >> > > >
> >> > > > During mouse unplugging from psaux connector from the laptops' docking
> >> > > > station I've got attached INFO trace.
> >> > > > (laptops still has synaptics device)
> >> > > >
> >> >
> >> > Dell?
> >> >
> >> > > > Also for unknown reason to me  psaux mouse & synaptic device do not
> >> > > > work somehow together - is it hw limitation
> >> > > > of /dev/input/mice  interface?
> >> > > > (USB mouse and synaptics do work quite well together)
> >> > > >
> >> > > > [ INFO: possible recursive locking detected ]
> >> > > > 2.6.27-rc1 #48
> >> > >
> >> > > (it's 2.6.27-rc1)
> >> > >
> >> >
> >> > Peter, here is the trace we talked about long time ago. For some reason
> >> > lockdep annotation only works once. If reconnect is forced or psmouse
> >> > module is reloaded lockdep starts complaining about passthrough port.
> >>
> >> Bit puzzling - and I don't have any ps2 hardware around to test with
> >> (nor do I normally use modules - but that is fixable of course).
> >>
> >> Does Rabin's patch help?
> >>
> >>   http://lkml.org/lkml/2008/8/7/329
> >>
> >
> > I doubt it resolves problem fully because it only takes care of module
> > unload. I can easily trip lockdep by reconnecting the device. Just to
> > give some more details about the problem:
> >
> >  - synaptics touchpads have a pass-through port that allows to connect
> >   either external mouse or maybe a trackpoint device. Both devices
> >   are represented by 'serio' structures and are handled by the same
> >   driver (psmouse).
> >
> >  - as far as I know we have proper locking there and lockdep
> >   annotatinos were added to lockdep to reflect the nesting of the
> >   serio ports.
> >
> >  - if child port (pass-through port) is destroyed and recreated (due
> >   to module unload, or because user requested reconnect through sysfs
> >   or system-initiated reconnect) lockdep starts complaining although
> >   the new child port should still have the same "depth" as the old
> >   one.
> >
> 
> Well just noticed this issue again in my log - during resume operation
> - thus no external mouse connection in the game this time:
> 

External mouse does not have to be connected, the fact that you have
a pass-through serio port is enough to trigger this warning.

-- 
Dmitry
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