Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic
On 09/18/2012 11:13 AM, Michael Wang wrote:
> This patch try to fix the BUG:
>
> [0.043953] BUG: scheduling while atomic: swapper/0/1/0x1002
> [0.044017] no locks held by swapper/0/1.
> [0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9
> #34
> [0.045861] Call Trace:
> [0.048071] [] __schedule_bug+0x5e/0x70
> [0.048890] [] __schedule+0x91/0xb10
> [0.049660] [] ? vsnprintf+0x33a/0x450
> [0.050444] [] ? lg_local_lock+0x6/0x70
> [0.051256] [] ? wait_for_xmitr+0x31/0x90
> [0.052019] [] ? do_raw_spin_unlock+0xa5/0xf0
> [0.052903] [] ? _raw_spin_unlock+0x22/0x30
> [0.053759] [] ? up+0x1b/0x70
> [0.054421] [] __cond_resched+0x1b/0x30
> [0.055228] [] _cond_resched+0x45/0x50
> [0.056020] [] mutex_lock_nested+0x28/0x370
> [0.056884] [] ? console_unlock+0x3a2/0x4e0
> [0.057741] [] __irq_alloc_descs+0x39/0x1c0
> [0.058589] [] io_apic_setup_irq_pin+0x2c/0x310
> [0.060042] [] setup_IO_APIC+0x101/0x744
> [0.060878] [] ? clear_IO_APIC+0x31/0x50
> [0.061695] [] native_smp_prepare_cpus+0x538/0x680
> [0.062644] [] ? do_one_initcall+0x12c/0x12c
> [0.063517] [] ? do_one_initcall+0x12c/0x12c
> [0.064016] [] kernel_init+0x4b/0x17f
> [0.064790] [] ? do_one_initcall+0x12c/0x12c
> [0.065660] [] kernel_thread_helper+0x6/0x10
>
> The process to trigger the BUG is:
>
> native_smp_prepare_cpus()
> preempt_disable() //preempt_count++
> __irq_alloc_descs()
> mutex_lock()
> might_sleep() //should_resched() return true
> __schedule()
> preempt_disable() //preempt_count++
> schedule_bug() //preempt_count > 1, report bug
>
> So the issue is that should_resched() should not return true while the preempt
> already disabled.
>
> This patch will fix the issue, then might_sleep() won't do schedule in atomic
> any more.
Could I get some comments on the patch?
Regards,
Michael Wang
>
> Reported-by: Fengguang Wu
> Signed-off-by: Michael Wang
> ---
> kernel/sched/core.c |2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index b38f00e..2b7cd15 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield)
>
> static inline int should_resched(void)
> {
> - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
> + return need_resched() && !preempt_count();
> }
>
> static void __cond_resched(void)
>
--
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Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic
On 10/06/2012 05:06 PM, Michael Wang wrote:
> On 09/26/2012 11:41 AM, Michael Wang wrote:
>> On 09/18/2012 11:13 AM, Michael Wang wrote:
>>> This patch try to fix the BUG:
>>>
>>> [0.043953] BUG: scheduling while atomic: swapper/0/1/0x1002
>>> [0.044017] no locks held by swapper/0/1.
>>> [0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9
>>> #34
>>> [0.045861] Call Trace:
>>> [0.048071] [] __schedule_bug+0x5e/0x70
>>> [0.048890] [] __schedule+0x91/0xb10
>>> [0.049660] [] ? vsnprintf+0x33a/0x450
>>> [0.050444] [] ? lg_local_lock+0x6/0x70
>>> [0.051256] [] ? wait_for_xmitr+0x31/0x90
>>> [0.052019] [] ? do_raw_spin_unlock+0xa5/0xf0
>>> [0.052903] [] ? _raw_spin_unlock+0x22/0x30
>>> [0.053759] [] ? up+0x1b/0x70
>>> [0.054421] [] __cond_resched+0x1b/0x30
>>> [0.055228] [] _cond_resched+0x45/0x50
>>> [0.056020] [] mutex_lock_nested+0x28/0x370
>>> [0.056884] [] ? console_unlock+0x3a2/0x4e0
>>> [0.057741] [] __irq_alloc_descs+0x39/0x1c0
>>> [0.058589] [] io_apic_setup_irq_pin+0x2c/0x310
>>> [0.060042] [] setup_IO_APIC+0x101/0x744
>>> [0.060878] [] ? clear_IO_APIC+0x31/0x50
>>> [0.061695] [] native_smp_prepare_cpus+0x538/0x680
>>> [0.062644] [] ? do_one_initcall+0x12c/0x12c
>>> [0.063517] [] ? do_one_initcall+0x12c/0x12c
>>> [0.064016] [] kernel_init+0x4b/0x17f
>>> [0.064790] [] ? do_one_initcall+0x12c/0x12c
>>> [0.065660] [] kernel_thread_helper+0x6/0x10
>>>
>>> The process to trigger the BUG is:
>>>
>>> native_smp_prepare_cpus()
>>> preempt_disable() //preempt_count++
>>> __irq_alloc_descs()
>>> mutex_lock()
>>> might_sleep() //should_resched() return true
>>> __schedule()
>>> preempt_disable() //preempt_count++
>>> schedule_bug() //preempt_count > 1, report bug
>>>
>>> So the issue is that should_resched() should not return true while the
>>> preempt
>>> already disabled.
>>
>> Hi, Peter
>>
>> Could we use this solution to fix the bug?
>
> Please tell me if it's wrong, I really want to help fix it.
Reset the destination, sorry for the terrible mailing skill...
Regards,
Michael Wang
>
> Regards,
> Michael Wang
>
>>
>> Regards,
>> Michael Wang
>>
>>>
>>> This patch will fix the issue, then might_sleep() won't do schedule in
>>> atomic
>>> any more.
>>>
>>> Reported-by: Fengguang Wu
>>> Signed-off-by: Michael Wang
>>> ---
>>> kernel/sched/core.c |2 +-
>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>>> index b38f00e..2b7cd15 100644
>>> --- a/kernel/sched/core.c
>>> +++ b/kernel/sched/core.c
>>> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield)
>>>
>>> static inline int should_resched(void)
>>> {
>>> - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
>>> + return need_resched() && !preempt_count();
>>> }
>>>
>>> static void __cond_resched(void)
>>>
>>
>
--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic
On 09/26/2012 11:41 AM, Michael Wang wrote:
> On 09/18/2012 11:13 AM, Michael Wang wrote:
>> This patch try to fix the BUG:
>>
>> [0.043953] BUG: scheduling while atomic: swapper/0/1/0x1002
>> [0.044017] no locks held by swapper/0/1.
>> [0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9
>> #34
>> [0.045861] Call Trace:
>> [0.048071] [] __schedule_bug+0x5e/0x70
>> [0.048890] [] __schedule+0x91/0xb10
>> [0.049660] [] ? vsnprintf+0x33a/0x450
>> [0.050444] [] ? lg_local_lock+0x6/0x70
>> [0.051256] [] ? wait_for_xmitr+0x31/0x90
>> [0.052019] [] ? do_raw_spin_unlock+0xa5/0xf0
>> [0.052903] [] ? _raw_spin_unlock+0x22/0x30
>> [0.053759] [] ? up+0x1b/0x70
>> [0.054421] [] __cond_resched+0x1b/0x30
>> [0.055228] [] _cond_resched+0x45/0x50
>> [0.056020] [] mutex_lock_nested+0x28/0x370
>> [0.056884] [] ? console_unlock+0x3a2/0x4e0
>> [0.057741] [] __irq_alloc_descs+0x39/0x1c0
>> [0.058589] [] io_apic_setup_irq_pin+0x2c/0x310
>> [0.060042] [] setup_IO_APIC+0x101/0x744
>> [0.060878] [] ? clear_IO_APIC+0x31/0x50
>> [0.061695] [] native_smp_prepare_cpus+0x538/0x680
>> [0.062644] [] ? do_one_initcall+0x12c/0x12c
>> [0.063517] [] ? do_one_initcall+0x12c/0x12c
>> [0.064016] [] kernel_init+0x4b/0x17f
>> [0.064790] [] ? do_one_initcall+0x12c/0x12c
>> [0.065660] [] kernel_thread_helper+0x6/0x10
>>
>> The process to trigger the BUG is:
>>
>> native_smp_prepare_cpus()
>> preempt_disable() //preempt_count++
>> __irq_alloc_descs()
>> mutex_lock()
>> might_sleep() //should_resched() return true
>> __schedule()
>> preempt_disable() //preempt_count++
>> schedule_bug() //preempt_count > 1, report bug
>>
>> So the issue is that should_resched() should not return true while the
>> preempt
>> already disabled.
>
> Hi, Peter
>
> Could we use this solution to fix the bug?
Please tell me if it's wrong, I really want to help fix it.
Regards,
Michael Wang
>
> Regards,
> Michael Wang
>
>>
>> This patch will fix the issue, then might_sleep() won't do schedule in atomic
>> any more.
>>
>> Reported-by: Fengguang Wu
>> Signed-off-by: Michael Wang
>> ---
>> kernel/sched/core.c |2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index b38f00e..2b7cd15 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield)
>>
>> static inline int should_resched(void)
>> {
>> -return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
>> +return need_resched() && !preempt_count();
>> }
>>
>> static void __cond_resched(void)
>>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sched: fix should_resched() to avoid do schedule in atomic
On 09/18/2012 11:13 AM, Michael Wang wrote:
> This patch try to fix the BUG:
>
> [0.043953] BUG: scheduling while atomic: swapper/0/1/0x1002
> [0.044017] no locks held by swapper/0/1.
> [0.044692] Pid: 1, comm: swapper/0 Not tainted 3.6.0-rc1-00420-gb7aebb9
> #34
> [0.045861] Call Trace:
> [0.048071] [] __schedule_bug+0x5e/0x70
> [0.048890] [] __schedule+0x91/0xb10
> [0.049660] [] ? vsnprintf+0x33a/0x450
> [0.050444] [] ? lg_local_lock+0x6/0x70
> [0.051256] [] ? wait_for_xmitr+0x31/0x90
> [0.052019] [] ? do_raw_spin_unlock+0xa5/0xf0
> [0.052903] [] ? _raw_spin_unlock+0x22/0x30
> [0.053759] [] ? up+0x1b/0x70
> [0.054421] [] __cond_resched+0x1b/0x30
> [0.055228] [] _cond_resched+0x45/0x50
> [0.056020] [] mutex_lock_nested+0x28/0x370
> [0.056884] [] ? console_unlock+0x3a2/0x4e0
> [0.057741] [] __irq_alloc_descs+0x39/0x1c0
> [0.058589] [] io_apic_setup_irq_pin+0x2c/0x310
> [0.060042] [] setup_IO_APIC+0x101/0x744
> [0.060878] [] ? clear_IO_APIC+0x31/0x50
> [0.061695] [] native_smp_prepare_cpus+0x538/0x680
> [0.062644] [] ? do_one_initcall+0x12c/0x12c
> [0.063517] [] ? do_one_initcall+0x12c/0x12c
> [0.064016] [] kernel_init+0x4b/0x17f
> [0.064790] [] ? do_one_initcall+0x12c/0x12c
> [0.065660] [] kernel_thread_helper+0x6/0x10
>
> The process to trigger the BUG is:
>
> native_smp_prepare_cpus()
> preempt_disable() //preempt_count++
> __irq_alloc_descs()
> mutex_lock()
> might_sleep() //should_resched() return true
> __schedule()
> preempt_disable() //preempt_count++
> schedule_bug() //preempt_count > 1, report bug
>
> So the issue is that should_resched() should not return true while the preempt
> already disabled.
Hi, Peter
Could we use this solution to fix the bug?
Regards,
Michael Wang
>
> This patch will fix the issue, then might_sleep() won't do schedule in atomic
> any more.
>
> Reported-by: Fengguang Wu
> Signed-off-by: Michael Wang
> ---
> kernel/sched/core.c |2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index b38f00e..2b7cd15 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4171,7 +4171,7 @@ SYSCALL_DEFINE0(sched_yield)
>
> static inline int should_resched(void)
> {
> - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
> + return need_resched() && !preempt_count();
> }
>
> static void __cond_resched(void)
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
