* new (common) WARNING message?
@ 2009-01-16 1:08 Mike Travis
2009-01-16 11:46 ` Stefan Richter
0 siblings, 1 reply; 4+ messages in thread
From: Mike Travis @ 2009-01-16 1:08 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: Ingo Molnar, Rusty Russell
Hi Thomas,
I've been seeing these on and off for a while now. They don't
seem to affect anything but perhaps I should track them down?
Do you know what it means? (I'm asking you because evidently
debugobjects.c is from you? I read the good explanation in the
changelog of 3ac7fe5a, but it didn't clue me into what's going
on. ;-)
Thanks,
Mike
--
[ 1294.973592] ODEBUG: object is on stack, but not annotated
[ 1294.974067] ------------[ cut here ]------------
[ 1294.974067] WARNING: at /mdata/lwork/polaris3/travis/workareas/ingo-latest/linux-2.6-for-ingo/lib/debugobjects.c:253 __debug_object_init+0x27c/0x2f0()
[ 1294.974067] Hardware name: X7DBT
[ 1294.974067] Pid: 4150, comm: offline-test Tainted: G W 2.6.29-rc1-4k-defconfig.01151634-00255-gc99dbbe-dirty #89
[ 1294.974067] Call Trace:
[ 1294.974067] [<ffffffff81047e3f>] warn_slowpath+0xd3/0xf2
[ 1294.974067] [<ffffffff8106c64f>] ? trace_hardirqs_off+0xd/0xf
[ 1294.974067] [<ffffffff815ca6ac>] ? _spin_unlock_irqrestore+0x3d/0x4c
[ 1294.974067] [<ffffffff8125bebe>] ? __debug_check_no_obj_freed+0xf6/0x14c
[ 1294.974067] [<ffffffff81048d3c>] ? printk+0x6c/0x6e
[ 1294.974067] [<ffffffff8125c449>] ? __debug_object_init+0xf9/0x2f0
[ 1294.974067] [<ffffffff8125b3ae>] ? _raw_spin_unlock+0xc7/0xf6
[ 1294.974067] [<ffffffff8125c5cc>] __debug_object_init+0x27c/0x2f0
[ 1294.974067] [<ffffffff8125c66d>] debug_object_init+0x14/0x17
[ 1294.974067] [<ffffffff81052320>] init_timer+0x1d/0x2a
[ 1294.974067] [<ffffffff81025077>] hpet_cpuhp_notify+0xad/0x124
[ 1294.974067] [<ffffffff81025233>] ? hpet_work+0x0/0x21a
[ 1294.974067] [<ffffffff81062057>] notifier_call_chain+0x33/0x5b
[ 1294.974067] [<ffffffff810620ad>] __raw_notifier_call_chain+0xe/0x10
[ 1294.974067] [<ffffffff810620c3>] raw_notifier_call_chain+0x14/0x16
[ 1294.974067] [<ffffffff815c5190>] _cpu_up+0x115/0x155
[ 1294.974067] [<ffffffff815c527c>] cpu_up+0x65/0x73
[ 1294.974067] [<ffffffff815ac21d>] store_online+0x52/0x7b
[ 1294.974067] [<ffffffff812ff775>] sysdev_store+0x20/0x22
[ 1294.974067] [<ffffffff81134f6b>] sysfs_write_file+0xe9/0x11e
[ 1294.974067] [<ffffffff810e0da5>] vfs_write+0xea/0x148
[ 1294.974067] [<ffffffff810e0ec7>] sys_write+0x4c/0x72
[ 1294.974067] [<ffffffff8100c6cb>] system_call_fastpath+0x16/0x1b
[ 1294.974067] ---[ end trace 4eaa2a86a8e2da24 ]---
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: new (common) WARNING message?
2009-01-16 1:08 new (common) WARNING message? Mike Travis
@ 2009-01-16 11:46 ` Stefan Richter
2009-01-16 13:01 ` Ingo Molnar
2009-01-16 18:48 ` Mike Travis
0 siblings, 2 replies; 4+ messages in thread
From: Stefan Richter @ 2009-01-16 11:46 UTC (permalink / raw)
To: Mike Travis; +Cc: Thomas Gleixner, LKML, Ingo Molnar, Rusty Russell
Mike Travis wrote:
> I've been seeing these on and off for a while now. They don't
> seem to affect anything but perhaps I should track them down?
>
> Do you know what it means? (I'm asking you because evidently
> debugobjects.c is from you? I read the good explanation in the
> changelog of 3ac7fe5a, but it didn't clue me into what's going
> on. ;-)
>
> Thanks,
> Mike
> --
>
> [ 1294.973592] ODEBUG: object is on stack, but not annotated
> [ 1294.974067] ------------[ cut here ]------------
> [ 1294.974067] WARNING: at /mdata/lwork/polaris3/travis/workareas/ingo-latest/linux-2.6-for-ingo/lib/debugobjects.c:253 __debug_object_init+0x27c/0x2f0()
> [ 1294.974067] Hardware name: X7DBT
> [ 1294.974067] Pid: 4150, comm: offline-test Tainted: G W 2.6.29-rc1-4k-defconfig.01151634-00255-gc99dbbe-dirty #89
> [ 1294.974067] Call Trace:
> [ 1294.974067] [<ffffffff81047e3f>] warn_slowpath+0xd3/0xf2
> [ 1294.974067] [<ffffffff8106c64f>] ? trace_hardirqs_off+0xd/0xf
> [ 1294.974067] [<ffffffff815ca6ac>] ? _spin_unlock_irqrestore+0x3d/0x4c
> [ 1294.974067] [<ffffffff8125bebe>] ? __debug_check_no_obj_freed+0xf6/0x14c
> [ 1294.974067] [<ffffffff81048d3c>] ? printk+0x6c/0x6e
> [ 1294.974067] [<ffffffff8125c449>] ? __debug_object_init+0xf9/0x2f0
> [ 1294.974067] [<ffffffff8125b3ae>] ? _raw_spin_unlock+0xc7/0xf6
> [ 1294.974067] [<ffffffff8125c5cc>] __debug_object_init+0x27c/0x2f0
> [ 1294.974067] [<ffffffff8125c66d>] debug_object_init+0x14/0x17
> [ 1294.974067] [<ffffffff81052320>] init_timer+0x1d/0x2a
> [ 1294.974067] [<ffffffff81025077>] hpet_cpuhp_notify+0xad/0x124
> [ 1294.974067] [<ffffffff81025233>] ? hpet_work+0x0/0x21a
> [ 1294.974067] [<ffffffff81062057>] notifier_call_chain+0x33/0x5b
> [ 1294.974067] [<ffffffff810620ad>] __raw_notifier_call_chain+0xe/0x10
> [ 1294.974067] [<ffffffff810620c3>] raw_notifier_call_chain+0x14/0x16
> [ 1294.974067] [<ffffffff815c5190>] _cpu_up+0x115/0x155
> [ 1294.974067] [<ffffffff815c527c>] cpu_up+0x65/0x73
> [ 1294.974067] [<ffffffff815ac21d>] store_online+0x52/0x7b
> [ 1294.974067] [<ffffffff812ff775>] sysdev_store+0x20/0x22
> [ 1294.974067] [<ffffffff81134f6b>] sysfs_write_file+0xe9/0x11e
> [ 1294.974067] [<ffffffff810e0da5>] vfs_write+0xea/0x148
> [ 1294.974067] [<ffffffff810e0ec7>] sys_write+0x4c/0x72
> [ 1294.974067] [<ffffffff8100c6cb>] system_call_fastpath+0x16/0x1b
> [ 1294.974067] ---[ end trace 4eaa2a86a8e2da24 ]---
> --
The warning tells us that arch/x86/kernel/hpet.c::hpet_cpuhp_notify()
allocates a timer on the stack. In particular, it allocates a struct
hpet_work_struct on the stack which incorporates a timer.
Now, a timer instance on a stack would be wrong if the function which
defined that timer exits too early. But in case of hpet_cpuhp_notify(),
this is OK since
- it waits for the work be done,
- the work does not rearm itself.
IOW the work and thus the timer won't be accessed anymore when
hpet_cpuhp_notify() returns.
So, hpet_cpuhp_notify() apparently needs a variant of INIT_DELAYED_WORK
which uses init_timer_on_stack instead of init_timer, to say "trust me,
I know what I'm doing".
--
Stefan Richter
-=====-==--= ---= =----
http://arcgraph.de/sr/
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: new (common) WARNING message?
2009-01-16 11:46 ` Stefan Richter
@ 2009-01-16 13:01 ` Ingo Molnar
2009-01-16 18:48 ` Mike Travis
1 sibling, 0 replies; 4+ messages in thread
From: Ingo Molnar @ 2009-01-16 13:01 UTC (permalink / raw)
To: Stefan Richter; +Cc: Mike Travis, Thomas Gleixner, LKML, Rusty Russell
* Stefan Richter <stefanr@s5r6.in-berlin.de> wrote:
> Mike Travis wrote:
> > I've been seeing these on and off for a while now. They don't
> > seem to affect anything but perhaps I should track them down?
> >
> > Do you know what it means? (I'm asking you because evidently
> > debugobjects.c is from you? I read the good explanation in the
> > changelog of 3ac7fe5a, but it didn't clue me into what's going
> > on. ;-)
> >
> > Thanks,
> > Mike
> > --
> >
> > [ 1294.973592] ODEBUG: object is on stack, but not annotated
> > [ 1294.974067] ------------[ cut here ]------------
> > [ 1294.974067] WARNING: at /mdata/lwork/polaris3/travis/workareas/ingo-latest/linux-2.6-for-ingo/lib/debugobjects.c:253 __debug_object_init+0x27c/0x2f0()
> > [ 1294.974067] Hardware name: X7DBT
> > [ 1294.974067] Pid: 4150, comm: offline-test Tainted: G W 2.6.29-rc1-4k-defconfig.01151634-00255-gc99dbbe-dirty #89
> > [ 1294.974067] Call Trace:
> > [ 1294.974067] [<ffffffff81047e3f>] warn_slowpath+0xd3/0xf2
> > [ 1294.974067] [<ffffffff8106c64f>] ? trace_hardirqs_off+0xd/0xf
> > [ 1294.974067] [<ffffffff815ca6ac>] ? _spin_unlock_irqrestore+0x3d/0x4c
> > [ 1294.974067] [<ffffffff8125bebe>] ? __debug_check_no_obj_freed+0xf6/0x14c
> > [ 1294.974067] [<ffffffff81048d3c>] ? printk+0x6c/0x6e
> > [ 1294.974067] [<ffffffff8125c449>] ? __debug_object_init+0xf9/0x2f0
> > [ 1294.974067] [<ffffffff8125b3ae>] ? _raw_spin_unlock+0xc7/0xf6
> > [ 1294.974067] [<ffffffff8125c5cc>] __debug_object_init+0x27c/0x2f0
> > [ 1294.974067] [<ffffffff8125c66d>] debug_object_init+0x14/0x17
> > [ 1294.974067] [<ffffffff81052320>] init_timer+0x1d/0x2a
> > [ 1294.974067] [<ffffffff81025077>] hpet_cpuhp_notify+0xad/0x124
> > [ 1294.974067] [<ffffffff81025233>] ? hpet_work+0x0/0x21a
> > [ 1294.974067] [<ffffffff81062057>] notifier_call_chain+0x33/0x5b
> > [ 1294.974067] [<ffffffff810620ad>] __raw_notifier_call_chain+0xe/0x10
> > [ 1294.974067] [<ffffffff810620c3>] raw_notifier_call_chain+0x14/0x16
> > [ 1294.974067] [<ffffffff815c5190>] _cpu_up+0x115/0x155
> > [ 1294.974067] [<ffffffff815c527c>] cpu_up+0x65/0x73
> > [ 1294.974067] [<ffffffff815ac21d>] store_online+0x52/0x7b
> > [ 1294.974067] [<ffffffff812ff775>] sysdev_store+0x20/0x22
> > [ 1294.974067] [<ffffffff81134f6b>] sysfs_write_file+0xe9/0x11e
> > [ 1294.974067] [<ffffffff810e0da5>] vfs_write+0xea/0x148
> > [ 1294.974067] [<ffffffff810e0ec7>] sys_write+0x4c/0x72
> > [ 1294.974067] [<ffffffff8100c6cb>] system_call_fastpath+0x16/0x1b
> > [ 1294.974067] ---[ end trace 4eaa2a86a8e2da24 ]---
> > --
>
> The warning tells us that arch/x86/kernel/hpet.c::hpet_cpuhp_notify()
> allocates a timer on the stack. In particular, it allocates a struct
> hpet_work_struct on the stack which incorporates a timer.
>
> Now, a timer instance on a stack would be wrong if the function which
> defined that timer exits too early. But in case of hpet_cpuhp_notify(),
> this is OK since
> - it waits for the work be done,
> - the work does not rearm itself.
> IOW the work and thus the timer won't be accessed anymore when
> hpet_cpuhp_notify() returns.
>
> So, hpet_cpuhp_notify() apparently needs a variant of INIT_DELAYED_WORK
> which uses init_timer_on_stack instead of init_timer, to say "trust me,
> I know what I'm doing".
that's already fixed in tip/timers/urgent and queued up for Linus:
6d612b0: locking, hpet: annotate false positive warning
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: new (common) WARNING message?
2009-01-16 11:46 ` Stefan Richter
2009-01-16 13:01 ` Ingo Molnar
@ 2009-01-16 18:48 ` Mike Travis
1 sibling, 0 replies; 4+ messages in thread
From: Mike Travis @ 2009-01-16 18:48 UTC (permalink / raw)
To: Stefan Richter; +Cc: Thomas Gleixner, LKML, Ingo Molnar, Rusty Russell
Stefan Richter wrote:
> Mike Travis wrote:
>> I've been seeing these on and off for a while now. They don't
>> seem to affect anything but perhaps I should track them down?
>>
>> Do you know what it means? (I'm asking you because evidently
>> debugobjects.c is from you? I read the good explanation in the
>> changelog of 3ac7fe5a, but it didn't clue me into what's going
>> on. ;-)
>>
>> Thanks,
>> Mike
>> --
>>
>> [ 1294.973592] ODEBUG: object is on stack, but not annotated
>> [ 1294.974067] ------------[ cut here ]------------
>> [ 1294.974067] WARNING: at /mdata/lwork/polaris3/travis/workareas/ingo-latest/linux-2.6-for-ingo/lib/debugobjects.c:253 __debug_object_init+0x27c/0x2f0()
>> [ 1294.974067] Hardware name: X7DBT
>> [ 1294.974067] Pid: 4150, comm: offline-test Tainted: G W 2.6.29-rc1-4k-defconfig.01151634-00255-gc99dbbe-dirty #89
>> [ 1294.974067] Call Trace:
>> [ 1294.974067] [<ffffffff81047e3f>] warn_slowpath+0xd3/0xf2
>> [ 1294.974067] [<ffffffff8106c64f>] ? trace_hardirqs_off+0xd/0xf
>> [ 1294.974067] [<ffffffff815ca6ac>] ? _spin_unlock_irqrestore+0x3d/0x4c
>> [ 1294.974067] [<ffffffff8125bebe>] ? __debug_check_no_obj_freed+0xf6/0x14c
>> [ 1294.974067] [<ffffffff81048d3c>] ? printk+0x6c/0x6e
>> [ 1294.974067] [<ffffffff8125c449>] ? __debug_object_init+0xf9/0x2f0
>> [ 1294.974067] [<ffffffff8125b3ae>] ? _raw_spin_unlock+0xc7/0xf6
>> [ 1294.974067] [<ffffffff8125c5cc>] __debug_object_init+0x27c/0x2f0
>> [ 1294.974067] [<ffffffff8125c66d>] debug_object_init+0x14/0x17
>> [ 1294.974067] [<ffffffff81052320>] init_timer+0x1d/0x2a
>> [ 1294.974067] [<ffffffff81025077>] hpet_cpuhp_notify+0xad/0x124
>> [ 1294.974067] [<ffffffff81025233>] ? hpet_work+0x0/0x21a
>> [ 1294.974067] [<ffffffff81062057>] notifier_call_chain+0x33/0x5b
>> [ 1294.974067] [<ffffffff810620ad>] __raw_notifier_call_chain+0xe/0x10
>> [ 1294.974067] [<ffffffff810620c3>] raw_notifier_call_chain+0x14/0x16
>> [ 1294.974067] [<ffffffff815c5190>] _cpu_up+0x115/0x155
>> [ 1294.974067] [<ffffffff815c527c>] cpu_up+0x65/0x73
>> [ 1294.974067] [<ffffffff815ac21d>] store_online+0x52/0x7b
>> [ 1294.974067] [<ffffffff812ff775>] sysdev_store+0x20/0x22
>> [ 1294.974067] [<ffffffff81134f6b>] sysfs_write_file+0xe9/0x11e
>> [ 1294.974067] [<ffffffff810e0da5>] vfs_write+0xea/0x148
>> [ 1294.974067] [<ffffffff810e0ec7>] sys_write+0x4c/0x72
>> [ 1294.974067] [<ffffffff8100c6cb>] system_call_fastpath+0x16/0x1b
>> [ 1294.974067] ---[ end trace 4eaa2a86a8e2da24 ]---
>> --
>
> The warning tells us that arch/x86/kernel/hpet.c::hpet_cpuhp_notify()
> allocates a timer on the stack. In particular, it allocates a struct
> hpet_work_struct on the stack which incorporates a timer.
>
> Now, a timer instance on a stack would be wrong if the function which
> defined that timer exits too early. But in case of hpet_cpuhp_notify(),
> this is OK since
> - it waits for the work be done,
> - the work does not rearm itself.
> IOW the work and thus the timer won't be accessed anymore when
> hpet_cpuhp_notify() returns.
>
> So, hpet_cpuhp_notify() apparently needs a variant of INIT_DELAYED_WORK
> which uses init_timer_on_stack instead of init_timer, to say "trust me,
> I know what I'm doing".
Hi Stefan,
Thanks for the great explanation!
Cheers,
Mike
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-01-16 18:48 UTC | newest]
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2009-01-16 1:08 new (common) WARNING message? Mike Travis
2009-01-16 11:46 ` Stefan Richter
2009-01-16 13:01 ` Ingo Molnar
2009-01-16 18:48 ` Mike Travis
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