Hello Maintainers:
Under my x86_64 dual core laptop, I build kernel next-20130927 with
'allmodconfig', and install it, the machine can not start. Related
information is:
after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
fail in another place). I guess, the reason is my laptop cpu is not
'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
I will continue analyzing, welcome any additional suggestions or
completions.
Thanks.
--
Chen Gang
On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
> Hello Maintainers:
>
> Under my x86_64 dual core laptop, I build kernel next-20130927 with
> 'allmodconfig', and install it, the machine can not start. Related
> information is:
>
> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
>
> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
> fail in another place). I guess, the reason is my laptop cpu is not
> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
>
>
> I will continue analyzing, welcome any additional suggestions or
> completions.
allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
"def_bool n"), which puts CPU0 offline during boot for testing. This
debug feature is causing the problem on your laptop. I am not familiar
with allmodconfig, but it seems that it enables all the config options,
preferably with 'm'.
Thanks,
-Toshi
On 10/02/2013 11:28 PM, Toshi Kani wrote:
> On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
>> Hello Maintainers:
>>
>> Under my x86_64 dual core laptop, I build kernel next-20130927 with
>> 'allmodconfig', and install it, the machine can not start. Related
>> information is:
>>
>> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
>>
>> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
>> fail in another place). I guess, the reason is my laptop cpu is not
>> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
>>
>>
>> I will continue analyzing, welcome any additional suggestions or
>> completions.
>
> allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
> "def_bool n"), which puts CPU0 offline during boot for testing. This
> debug feature is causing the problem on your laptop. I am not familiar
> with allmodconfig, but it seems that it enables all the config options,
> preferably with 'm'.
>
Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
it still can work or not. If any members know about it, please tell me,
thanks.
In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
offline for laptop", we need let 'offline' operation fail.
And I am analyzing (just constructing environments: KVM, kgdb ...),
before let kernel start successfully, only according to my current
proofs, we can not say "let laptop cpu0 offline" must be an issue.
Thanks.
> Thanks,
> -Toshi
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
Thanks.
--
Chen Gang
On Thu, 2013-10-03 at 00:41 +0800, Chen Gang F T wrote:
> On 10/02/2013 11:28 PM, Toshi Kani wrote:
> > On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
> >> Hello Maintainers:
> >>
> >> Under my x86_64 dual core laptop, I build kernel next-20130927 with
> >> 'allmodconfig', and install it, the machine can not start. Related
> >> information is:
> >>
> >> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
> >>
> >> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
> >> fail in another place). I guess, the reason is my laptop cpu is not
> >> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
> >>
> >>
> >> I will continue analyzing, welcome any additional suggestions or
> >> completions.
> >
> > allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
> > "def_bool n"), which puts CPU0 offline during boot for testing. This
> > debug feature is causing the problem on your laptop. I am not familiar
> > with allmodconfig, but it seems that it enables all the config options,
> > preferably with 'm'.
> >
>
> Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
> it still can work or not. If any members know about it, please tell me,
> thanks.
CPU online/offline works on laptops as long as they have more than one
CPU. You can boot with other kernel and test this feature
with /sys/devices/system/cpu/cpuX/online on your laptop. cpu0 is a
special case and you may need to specify "cpu0_hotplug" boot option.
> In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
> offline for laptop", we need let 'offline' operation fail.
Whether it is a laptop or not should not be a matter here. But I agree
with you that enabling CONFIG_DEBUG_HOTPLUG_CPU0 is not useful (and can
be harmful) unless a user really intends to test this feature.
Thanks,
-Toshi
> And I am analyzing (just constructing environments: KVM, kgdb ...),
> before let kernel start successfully, only according to my current
> proofs, we can not say "let laptop cpu0 offline" must be an issue.
On 10/03/2013 03:33 AM, Toshi Kani wrote:
> On Thu, 2013-10-03 at 00:41 +0800, Chen Gang F T wrote:
>> On 10/02/2013 11:28 PM, Toshi Kani wrote:
>>> On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
>>>> Hello Maintainers:
>>>>
>>>> Under my x86_64 dual core laptop, I build kernel next-20130927 with
>>>> 'allmodconfig', and install it, the machine can not start. Related
>>>> information is:
>>>>
>>>> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
>>>>
>>>> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
>>>> fail in another place). I guess, the reason is my laptop cpu is not
>>>> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
>>>>
>>>>
>>>> I will continue analyzing, welcome any additional suggestions or
>>>> completions.
>>>
>>> allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
>>> "def_bool n"), which puts CPU0 offline during boot for testing. This
>>> debug feature is causing the problem on your laptop. I am not familiar
>>> with allmodconfig, but it seems that it enables all the config options,
>>> preferably with 'm'.
>>>
>>
>> Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
>> it still can work or not. If any members know about it, please tell me,
>> thanks.
>
> CPU online/offline works on laptops as long as they have more than one
> CPU. You can boot with other kernel and test this feature
> with /sys/devices/system/cpu/cpuX/online on your laptop. cpu0 is a
> special case and you may need to specify "cpu0_hotplug" boot option.
>
Thank you for your confirmation, "for dual core (although laptop), after
system boot up, can let cpu0 offline". :-)
>> In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
>> offline for laptop", we need let 'offline' operation fail.
>
> Whether it is a laptop or not should not be a matter here. But I agree
> with you that enabling CONFIG_DEBUG_HOTPLUG_CPU0 is not useful (and can
> be harmful) unless a user really intends to test this feature.
>
Hmm... I will continue analyzing. After finish analyzing (let kernel
boot up OK), I should give a confirmation: "during boot up, can we still
let cpu0 offline for dual core?".
In fact, 'allmodconfig' is just a mad user which often does useless
things to intend to find issues.
Thanks.
> Thanks,
> -Toshi
>
>> And I am analyzing (just constructing environments: KVM, kgdb ...),
>> before let kernel start successfully, only according to my current
>> proofs, we can not say "let laptop cpu0 offline" must be an issue.
>
>
>
>
>
--
Chen Gang
One root cause found (but not only one), allmodconfig will enable
CONFIG_SYSFS_DEPRECATED which for new kernel on old distribution.
I am comparing from allmodconfig config file to defconfig config file,
the attachments are middle files (one enable CONFIG_SYSFS_DEPRECATED
which can not boot up, the other disable it which can boot up).
The related information in "init/Kconfig"
config SYSFS_DEPRECATED
bool "Enable deprecated sysfs features to support old userspace tools"
depends on SYSFS
default n
help
This option adds code that switches the layout of the "block" class
devices, to not show up in /sys/class/block/, but only in
/sys/block/.
This switch is only active when the sysfs.deprecated=1 boot option is
passed or the SYSFS_DEPRECATED_V2 option is set.
This option allows new kernels to run on old distributions and tools,
which might get confused by /sys/class/block/. Since 2007/2008 all
major distributions and tools handle this just fine.
Recent distributions and userspace tools after 2009/2010 depend on
the existence of /sys/class/block/, and will not work with this
option enabled.
Only if you are using a new kernel on an old distribution, you might
need to say Y here.
I will continue to analyze another related issues for allmodconfig on
my laptop (after disable SYSFS_DEPRECATED, for allmodconfig, it still
can not boot up successfully, although my 'middle' config file can).
BTW: for defconfig on my PC (x86_64 dual core, fedora 17), need enable
"Device Drivers" -> "Generic Driver Options" -> "Maintain a devtmpfs
...", or can not start up. is it suitable to send related patch for it?
Thanks.
On 10/03/2013 08:49 AM, Chen Gang wrote:
> On 10/03/2013 03:33 AM, Toshi Kani wrote:
>> On Thu, 2013-10-03 at 00:41 +0800, Chen Gang F T wrote:
>>> On 10/02/2013 11:28 PM, Toshi Kani wrote:
>>>> On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
>>>>> Hello Maintainers:
>>>>>
>>>>> Under my x86_64 dual core laptop, I build kernel next-20130927 with
>>>>> 'allmodconfig', and install it, the machine can not start. Related
>>>>> information is:
>>>>>
>>>>> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
>>>>>
>>>>> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
>>>>> fail in another place). I guess, the reason is my laptop cpu is not
>>>>> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
>>>>>
>>>>>
>>>>> I will continue analyzing, welcome any additional suggestions or
>>>>> completions.
>>>>
>>>> allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
>>>> "def_bool n"), which puts CPU0 offline during boot for testing. This
>>>> debug feature is causing the problem on your laptop. I am not familiar
>>>> with allmodconfig, but it seems that it enables all the config options,
>>>> preferably with 'm'.
>>>>
>>>
>>> Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
>>> it still can work or not. If any members know about it, please tell me,
>>> thanks.
>>
>> CPU online/offline works on laptops as long as they have more than one
>> CPU. You can boot with other kernel and test this feature
>> with /sys/devices/system/cpu/cpuX/online on your laptop. cpu0 is a
>> special case and you may need to specify "cpu0_hotplug" boot option.
>>
>
> Thank you for your confirmation, "for dual core (although laptop), after
> system boot up, can let cpu0 offline". :-)
>
>>> In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
>>> offline for laptop", we need let 'offline' operation fail.
>>
>> Whether it is a laptop or not should not be a matter here. But I agree
>> with you that enabling CONFIG_DEBUG_HOTPLUG_CPU0 is not useful (and can
>> be harmful) unless a user really intends to test this feature.
>>
>
> Hmm... I will continue analyzing. After finish analyzing (let kernel
> boot up OK), I should give a confirmation: "during boot up, can we still
> let cpu0 offline for dual core?".
>
> In fact, 'allmodconfig' is just a mad user which often does useless
> things to intend to find issues.
>
> Thanks.
>
>> Thanks,
>> -Toshi
>>
>>> And I am analyzing (just constructing environments: KVM, kgdb ...),
>>> before let kernel start successfully, only according to my current
>>> proofs, we can not say "let laptop cpu0 offline" must be an issue.
>>
>>
>>
>>
>>
>
>
--
Chen Gang
On Thu, 2013-10-03 at 00:49 +0000, Chen Gang wrote:
> On 10/03/2013 03:33 AM, Toshi Kani wrote:
> > On Thu, 2013-10-03 at 00:41 +0800, Chen Gang F T wrote:
> >> On 10/02/2013 11:28 PM, Toshi Kani wrote:
> >>> On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
> >>>> Hello Maintainers:
> >>>>
> >>>> Under my x86_64 dual core laptop, I build kernel next-20130927 with
> >>>> 'allmodconfig', and install it, the machine can not start. Related
> >>>> information is:
> >>>>
> >>>> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
> >>>>
> >>>> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
> >>>> fail in another place). I guess, the reason is my laptop cpu is not
> >>>> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
> >>>>
> >>>>
> >>>> I will continue analyzing, welcome any additional suggestions or
> >>>> completions.
> >>>
> >>> allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
> >>> "def_bool n"), which puts CPU0 offline during boot for testing. This
> >>> debug feature is causing the problem on your laptop. I am not familiar
> >>> with allmodconfig, but it seems that it enables all the config options,
> >>> preferably with 'm'.
> >>>
> >>
> >> Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
> >> it still can work or not. If any members know about it, please tell me,
> >> thanks.
> >
> > CPU online/offline works on laptops as long as they have more than one
> > CPU. You can boot with other kernel and test this feature
> > with /sys/devices/system/cpu/cpuX/online on your laptop. cpu0 is a
> > special case and you may need to specify "cpu0_hotplug" boot option.
> >
>
> Thank you for your confirmation, "for dual core (although laptop), after
> system boot up, can let cpu0 offline". :-)
Good. :)
> >> In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
> >> offline for laptop", we need let 'offline' operation fail.
> >
> > Whether it is a laptop or not should not be a matter here. But I agree
> > with you that enabling CONFIG_DEBUG_HOTPLUG_CPU0 is not useful (and can
> > be harmful) unless a user really intends to test this feature.
> >
>
> Hmm... I will continue analyzing. After finish analyzing (let kernel
> boot up OK), I should give a confirmation: "during boot up, can we still
> let cpu0 offline for dual core?".
>
> In fact, 'allmodconfig' is just a mad user which often does useless
> things to intend to find issues.
I see. If this option is used for testing, enabling DEBUG_HOTPLUG_CPU0
does make sense.
Thanks,
-Toshi
On Thu, 2013-10-03 at 22:21 +0800, Chen Gang wrote:
> One root cause found (but not only one), allmodconfig will enable
> CONFIG_SYSFS_DEPRECATED which for new kernel on old distribution.
>
>
> I am comparing from allmodconfig config file to defconfig config file,
> the attachments are middle files (one enable CONFIG_SYSFS_DEPRECATED
> which can not boot up, the other disable it which can boot up).
>
> The related information in "init/Kconfig"
>
> config SYSFS_DEPRECATED
> bool "Enable deprecated sysfs features to support old userspace tools"
> depends on SYSFS
> default n
> help
> This option adds code that switches the layout of the "block" class
> devices, to not show up in /sys/class/block/, but only in
> /sys/block/.
>
> This switch is only active when the sysfs.deprecated=1 boot option is
> passed or the SYSFS_DEPRECATED_V2 option is set.
>
> This option allows new kernels to run on old distributions and tools,
> which might get confused by /sys/class/block/. Since 2007/2008 all
> major distributions and tools handle this just fine.
>
> Recent distributions and userspace tools after 2009/2010 depend on
> the existence of /sys/class/block/, and will not work with this
> option enabled.
>
> Only if you are using a new kernel on an old distribution, you might
> need to say Y here.
>
>
> I will continue to analyze another related issues for allmodconfig on
> my laptop (after disable SYSFS_DEPRECATED, for allmodconfig, it still
> can not boot up successfully, although my 'middle' config file can).
Since this is no longer a hotplug issue, I'd suggest you change the
subject line and resend it to the folks who worked on this config
option. I won't be able to help on this one.
-Toshi
On 10/03/2013 11:07 PM, Toshi Kani wrote:
> On Thu, 2013-10-03 at 22:21 +0800, Chen Gang wrote:
>> One root cause found (but not only one), allmodconfig will enable
>> CONFIG_SYSFS_DEPRECATED which for new kernel on old distribution.
>>
>>
>> I am comparing from allmodconfig config file to defconfig config file,
>> the attachments are middle files (one enable CONFIG_SYSFS_DEPRECATED
>> which can not boot up, the other disable it which can boot up).
>>
>> The related information in "init/Kconfig"
>>
>> config SYSFS_DEPRECATED
>> bool "Enable deprecated sysfs features to support old userspace tools"
>> depends on SYSFS
>> default n
>> help
>> This option adds code that switches the layout of the "block" class
>> devices, to not show up in /sys/class/block/, but only in
>> /sys/block/.
>>
>> This switch is only active when the sysfs.deprecated=1 boot option is
>> passed or the SYSFS_DEPRECATED_V2 option is set.
>>
>> This option allows new kernels to run on old distributions and tools,
>> which might get confused by /sys/class/block/. Since 2007/2008 all
>> major distributions and tools handle this just fine.
>>
>> Recent distributions and userspace tools after 2009/2010 depend on
>> the existence of /sys/class/block/, and will not work with this
>> option enabled.
>>
>> Only if you are using a new kernel on an old distribution, you might
>> need to say Y here.
>>
>>
>> I will continue to analyze another related issues for allmodconfig on
>> my laptop (after disable SYSFS_DEPRECATED, for allmodconfig, it still
>> can not boot up successfully, although my 'middle' config file can).
>
> Since this is no longer a hotplug issue, I'd suggest you change the
> subject line and resend it to the folks who worked on this config
> option. I won't be able to help on this one.
>
OK, thanks, I will/should send related information (or patch) to the
related members for continue discussing.
And again, thank you for spending your time on it (already provided
useful information)
:-)
> -Toshi
>
>
>
>
Thanks.
--
Chen Gang
On 10/03/2013 10:51 PM, Toshi Kani wrote:
> On Thu, 2013-10-03 at 00:49 +0000, Chen Gang wrote:
>> On 10/03/2013 03:33 AM, Toshi Kani wrote:
>>> On Thu, 2013-10-03 at 00:41 +0800, Chen Gang F T wrote:
>>>> On 10/02/2013 11:28 PM, Toshi Kani wrote:
>>>>> On Wed, 2013-10-02 at 03:10 +0000, Chen Gang wrote:
>>>>>> Hello Maintainers:
>>>>>>
>>>>>> Under my x86_64 dual core laptop, I build kernel next-20130927 with
>>>>>> 'allmodconfig', and install it, the machine can not start. Related
>>>>>> information is:
>>>>>>
>>>>>> after call debug_hotplug_cpu(), output "cpu 0 is offline" .... and then "Failed to execute /init".
>>>>>>
>>>>>> After remove "_debug_hotplug_cpu(0, 0);", can pass the issue (but will
>>>>>> fail in another place). I guess, the reason is my laptop cpu is not
>>>>>> 'hotplug', but have to call debug_hotplug_cpu() with allmodconfig.
>>>>>>
>>>>>>
>>>>>> I will continue analyzing, welcome any additional suggestions or
>>>>>> completions.
>>>>>
>>>>> allmodconfig sets CONFIG_DEBUG_HOTPLUG_CPU0 to y (which is defined as
>>>>> "def_bool n"), which puts CPU0 offline during boot for testing. This
>>>>> debug feature is causing the problem on your laptop. I am not familiar
>>>>> with allmodconfig, but it seems that it enables all the config options,
>>>>> preferably with 'm'.
>>>>>
>>>>
>>>> Hmm... excuse me, I don't know: for laptop, if cpu0 is offline, whether
>>>> it still can work or not. If any members know about it, please tell me,
>>>> thanks.
>>>
>>> CPU online/offline works on laptops as long as they have more than one
>>> CPU. You can boot with other kernel and test this feature
>>> with /sys/devices/system/cpu/cpuX/online on your laptop. cpu0 is a
>>> special case and you may need to specify "cpu0_hotplug" boot option.
>>>
>>
>> Thank you for your confirmation, "for dual core (although laptop), after
>> system boot up, can let cpu0 offline". :-)
>
> Good. :)
>
>>>> In my opinion, if enable DEBUG_HOTPLUG_CPU0, but "should not let cpu0
>>>> offline for laptop", we need let 'offline' operation fail.
>>>
>>> Whether it is a laptop or not should not be a matter here. But I agree
>>> with you that enabling CONFIG_DEBUG_HOTPLUG_CPU0 is not useful (and can
>>> be harmful) unless a user really intends to test this feature.
>>>
>>
>> Hmm... I will continue analyzing. After finish analyzing (let kernel
>> boot up OK), I should give a confirmation: "during boot up, can we still
>> let cpu0 offline for dual core?".
>>
>> In fact, 'allmodconfig' is just a mad user which often does useless
>> things to intend to find issues.
>
> I see. If this option is used for testing, enabling DEBUG_HOTPLUG_CPU0
> does make sense.
>
Thank you for your encouragement.
My current idea about testing/analyzing/fixing is:
can boot up in allmodconfig for x86, smp version on dual/one core cpu.
can boot up under other architectures in allmodconfig in kvm machine.
can boot up with defconfig on x86 and various virtual machines.
My original idea is to use outside testing tools (e.g. LTP) for kernel,
hope I won't delay again (I have delayed several times), before outside
testing, we need pass internal test firstly (at least, can boot up).
Thanks.
> Thanks,
> -Toshi
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
Chen Gang