* [BUG] parport issue on 2.6.29
@ 2009-05-21 20:26 Matheus Izvekov
2009-05-26 23:54 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Matheus Izvekov @ 2009-05-21 20:26 UTC (permalink / raw)
To: linux-kernel
This warning happens whenever a specific parallel port control app is run
without a device attached to it. After the first timeout, the app hangs,
and needs SIGKILL to exit.
WARNING: at kernel/sysctl.c:2021 unregister_sysctl_table+0xa3/0x110()
Hardware name:
Modules linked in:
Pid: 12161, comm: x-killer.exe Not tainted 2.6.29.4 #14
Call Trace:
[<ffffffff8024c910>] warn_slowpath+0xd0/0x130
[<ffffffff80269859>] ? sched_clock_cpu+0xb9/0x190
[<ffffffff802484b4>] ? try_to_wake_up+0x174/0x330
[<ffffffff80268554>] ? up+0x34/0x50
[<ffffffff8024d1cd>] ? release_console_sem+0x1bd/0x210
[<ffffffff80aaa4d4>] ? printk+0x67/0x69
[<ffffffff80254ec3>] unregister_sysctl_table+0xa3/0x110
[<ffffffff806b3128>] parport_device_proc_unregister+0x28/0x40
[<ffffffff806b05f5>] parport_unregister_device+0x15/0x180
[<ffffffff806a0acc>] pp_release+0xbc/0x1f0
[<ffffffff802d3883>] __fput+0xc3/0x1e0
[<ffffffff802d39bd>] fput+0x1d/0x30
[<ffffffff802d0220>] filp_close+0x50/0x80
[<ffffffff8024ec74>] put_files_struct+0x84/0xe0
[<ffffffff8024ed1e>] exit_files+0x4e/0x60
[<ffffffff80250696>] do_exit+0x196/0x930
[<ffffffff80250e6e>] do_group_exit+0x3e/0xb0
[<ffffffff8025bda4>] get_signal_to_deliver+0x2a4/0x420
[<ffffffff8020b7aa>] do_notify_resume+0xba/0x900
[<ffffffff8023c16e>] ? __wake_up+0x4e/0x70
[<ffffffff8026c4a9>] ? getnstimeofday+0x59/0xe0
[<ffffffff80267a09>] ? ktime_get_ts+0x59/0x60
[<ffffffff80274314>] ? compat_sys_futex+0xb4/0x140
[<ffffffff8020c8b5>] int_signal+0x12/0x17
--[ end trace ff1bd583c825c0c5 ]---
pdev0: unregistered pardevice
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [BUG] parport issue on 2.6.29
2009-05-21 20:26 [BUG] parport issue on 2.6.29 Matheus Izvekov
@ 2009-05-26 23:54 ` Andrew Morton
2009-05-27 1:00 ` Eric W. Biederman
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2009-05-26 23:54 UTC (permalink / raw)
To: Matheus Izvekov; +Cc: linux-kernel, Eric W. Biederman
On Thu, 21 May 2009 17:26:55 -0300
Matheus Izvekov <mizvekov@gmail.com> wrote:
> This warning happens whenever a specific parallel port control app is run
> without a device attached to it. After the first timeout, the app hangs,
> and needs SIGKILL to exit.
>
> WARNING: at kernel/sysctl.c:2021 unregister_sysctl_table+0xa3/0x110()
I guess this is
void unregister_sysctl_table(struct ctl_table_header * header)
{
might_sleep();
if (header == NULL)
return;
spin_lock(&sysctl_lock);
start_unregistering(header);
if (!--header->parent->count) {
WARN_ON(1);
> Hardware name:
> Modules linked in:
> Pid: 12161, comm: x-killer.exe Not tainted 2.6.29.4 #14
> Call Trace:
> [<ffffffff8024c910>] warn_slowpath+0xd0/0x130
> [<ffffffff80269859>] ? sched_clock_cpu+0xb9/0x190
> [<ffffffff802484b4>] ? try_to_wake_up+0x174/0x330
> [<ffffffff80268554>] ? up+0x34/0x50
> [<ffffffff8024d1cd>] ? release_console_sem+0x1bd/0x210
> [<ffffffff80aaa4d4>] ? printk+0x67/0x69
> [<ffffffff80254ec3>] unregister_sysctl_table+0xa3/0x110
> [<ffffffff806b3128>] parport_device_proc_unregister+0x28/0x40
> [<ffffffff806b05f5>] parport_unregister_device+0x15/0x180
> [<ffffffff806a0acc>] pp_release+0xbc/0x1f0
> [<ffffffff802d3883>] __fput+0xc3/0x1e0
> [<ffffffff802d39bd>] fput+0x1d/0x30
> [<ffffffff802d0220>] filp_close+0x50/0x80
> [<ffffffff8024ec74>] put_files_struct+0x84/0xe0
> [<ffffffff8024ed1e>] exit_files+0x4e/0x60
> [<ffffffff80250696>] do_exit+0x196/0x930
> [<ffffffff80250e6e>] do_group_exit+0x3e/0xb0
> [<ffffffff8025bda4>] get_signal_to_deliver+0x2a4/0x420
> [<ffffffff8020b7aa>] do_notify_resume+0xba/0x900
> [<ffffffff8023c16e>] ? __wake_up+0x4e/0x70
> [<ffffffff8026c4a9>] ? getnstimeofday+0x59/0xe0
> [<ffffffff80267a09>] ? ktime_get_ts+0x59/0x60
> [<ffffffff80274314>] ? compat_sys_futex+0xb4/0x140
> [<ffffffff8020c8b5>] int_signal+0x12/0x17
> --[ end trace ff1bd583c825c0c5 ]---
> pdev0: unregistered pardevice
<looks for explanatory code comments, gets disappointed>
Eric, can you please help decode the reason for this kernel warning?
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [BUG] parport issue on 2.6.29
2009-05-26 23:54 ` Andrew Morton
@ 2009-05-27 1:00 ` Eric W. Biederman
0 siblings, 0 replies; 3+ messages in thread
From: Eric W. Biederman @ 2009-05-27 1:00 UTC (permalink / raw)
To: Andrew Morton; +Cc: Matheus Izvekov, linux-kernel
Andrew Morton <akpm@linux-foundation.org> writes:
> On Thu, 21 May 2009 17:26:55 -0300
> Matheus Izvekov <mizvekov@gmail.com> wrote:
>
>> This warning happens whenever a specific parallel port control app is run
>> without a device attached to it. After the first timeout, the app hangs,
>> and needs SIGKILL to exit.
>>
>> WARNING: at kernel/sysctl.c:2021 unregister_sysctl_table+0xa3/0x110()
>
> I guess this is
>
> void unregister_sysctl_table(struct ctl_table_header * header)
> {
> might_sleep();
>
> if (header == NULL)
> return;
>
> spin_lock(&sysctl_lock);
> start_unregistering(header);
> if (!--header->parent->count) {
> WARN_ON(1);
>
>> Hardware name:
>> Modules linked in:
>> Pid: 12161, comm: x-killer.exe Not tainted 2.6.29.4 #14
>> Call Trace:
>> [<ffffffff8024c910>] warn_slowpath+0xd0/0x130
>> [<ffffffff80269859>] ? sched_clock_cpu+0xb9/0x190
>> [<ffffffff802484b4>] ? try_to_wake_up+0x174/0x330
>> [<ffffffff80268554>] ? up+0x34/0x50
>> [<ffffffff8024d1cd>] ? release_console_sem+0x1bd/0x210
>> [<ffffffff80aaa4d4>] ? printk+0x67/0x69
>> [<ffffffff80254ec3>] unregister_sysctl_table+0xa3/0x110
>> [<ffffffff806b3128>] parport_device_proc_unregister+0x28/0x40
>> [<ffffffff806b05f5>] parport_unregister_device+0x15/0x180
>> [<ffffffff806a0acc>] pp_release+0xbc/0x1f0
>> [<ffffffff802d3883>] __fput+0xc3/0x1e0
>> [<ffffffff802d39bd>] fput+0x1d/0x30
>> [<ffffffff802d0220>] filp_close+0x50/0x80
>> [<ffffffff8024ec74>] put_files_struct+0x84/0xe0
>> [<ffffffff8024ed1e>] exit_files+0x4e/0x60
>> [<ffffffff80250696>] do_exit+0x196/0x930
>> [<ffffffff80250e6e>] do_group_exit+0x3e/0xb0
>> [<ffffffff8025bda4>] get_signal_to_deliver+0x2a4/0x420
>> [<ffffffff8020b7aa>] do_notify_resume+0xba/0x900
>> [<ffffffff8023c16e>] ? __wake_up+0x4e/0x70
>> [<ffffffff8026c4a9>] ? getnstimeofday+0x59/0xe0
>> [<ffffffff80267a09>] ? ktime_get_ts+0x59/0x60
>> [<ffffffff80274314>] ? compat_sys_futex+0xb4/0x140
>> [<ffffffff8020c8b5>] int_signal+0x12/0x17
>> --[ end trace ff1bd583c825c0c5 ]---
>> pdev0: unregistered pardevice
>
> <looks for explanatory code comments, gets disappointed>
>
> Eric, can you please help decode the reason for this kernel warning?
Looks like fallout from when Al changed the semantics of sysctl. Requiring
sysctl tables to hang off of empty parent directories.
It looks the parent directory was already been unregistered by the
time we are unregistered.
I'm not current enough on the parport code to have a better clue.
As far as sysctl goes that condition should be essentially harmless, wrong
but harmless.
Eric
^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-05-21 20:26 [BUG] parport issue on 2.6.29 Matheus Izvekov
2009-05-26 23:54 ` Andrew Morton
2009-05-27 1:00 ` Eric W. Biederman
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