2009-02-09 21:05:44

by Andrew Morton

[permalink] [raw]
Subject: Re: [Bugme-new] [Bug 12680] New: Not having a VIA PadLock hardware incurs a long delay in probing on modules insertion attempt.


(switched to email. Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Mon, 9 Feb 2009 09:12:59 -0800 (PST)
[email protected] wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=12680
>
> Summary: Not having a VIA PadLock hardware incurs a long delay in
> probing on modules insertion attempt.
> Product: Drivers
> Version: 2.5
> KernelVersion: Any 2.6.29 release candidate
> Platform: All
> OS/Version: Linux
> Tree: Mainline
> Status: NEW
> Severity: normal
> Priority: P1
> Component: Other
> AssignedTo: [email protected]

hm, we don't seem to have a bugzilla category for crypto.

> ReportedBy: [email protected]
>
>
> Latest working kernel version: 2.6.28.4
> Earliest failing kernel version: 2.6.29-rc1

I'll ask Rafael to track this as a post-2.6.28 regression.

> Distribution:
> Hardware Environment: IA32 i686 Athlon model 10
> Software Environment: Pristine kernel 2.6.29-rc4-git1 + Debian Lenny/Sid
> Problem Description: Not having a VIA PadLock hardware incurs a long delay in
> probing on modules insertion attempt:
>
> I can't say whether this abnormally long probe delay occurs on "padlock_aes"
> or "padlock_sha" module insertion attempt or both.
>
> I do not have such hardware indeed.
>
> I've never observed this problem so far with Linux version <= 2.6.28.4 .
>
> Steps to reproduce:
>
> Power-on your system ;-)
>
> In hope my report will prove useful.
>

Neither of those drivers have changed in six months, so the breakage
must be elsewhere.

I guess this should be easy for others to reproduce.

How long is the "long" delay?

Please do this:

add "log_buf_len=1M" to the kernel boot command line
reboot

dmesg -n 8
modprobe padlock_aes &
sleep 1
echo t > /prog/sysrq-trigger
dmesg -s 1000000 > foo

and then send us `foo'. Pleas avoid wordwrapping it.

This will permit us to see where `modprobe' is getting stuck.

Thanks.



2009-02-09 22:01:27

by Valentin QUEQUET

[permalink] [raw]
Subject: Re: [Bugme-new] [Bug 12680] New: Not having a VIA PadLock hardware incurs a long delay in probing on modules insertion attempt.

Andrew Morton wrote :
>
> (switched to email. Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Mon, 9 Feb 2009 09:12:59 -0800 (PST)
> [email protected] wrote:
>
>> http://bugzilla.kernel.org/show_bug.cgi?id=12680
>>
>> Summary: Not having a VIA PadLock hardware incurs a long delay in
>> probing on modules insertion attempt.
>> Product: Drivers
>> Version: 2.5
>> KernelVersion: Any 2.6.29 release candidate
>> Platform: All
>> OS/Version: Linux
>> Tree: Mainline
>> Status: NEW
>> Severity: normal
>> Priority: P1
>> Component: Other
>> AssignedTo: [email protected]
>
> hm, we don't seem to have a bugzilla category for crypto.
>
>> ReportedBy: [email protected]
>>
>>
>> Latest working kernel version: 2.6.28.4
>> Earliest failing kernel version: 2.6.29-rc1
>
> I'll ask Rafael to track this as a post-2.6.28 regression.
>
>> Distribution:
>> Hardware Environment: IA32 i686 Athlon model 10
>> Software Environment: Pristine kernel 2.6.29-rc4-git1 + Debian Lenny/Sid
>> Problem Description: Not having a VIA PadLock hardware incurs a long delay in
>> probing on modules insertion attempt:
>>
>> I can't say whether this abnormally long probe delay occurs on "padlock_aes"
>> or "padlock_sha" module insertion attempt or both.
>>
>> I do not have such hardware indeed.
>>
>> I've never observed this problem so far with Linux version <= 2.6.28.4 .
>>
>> Steps to reproduce:
>>
>> Power-on your system ;-)
>>
>> In hope my report will prove useful.
>>
>
> Neither of those drivers have changed in six months, so the breakage
> must be elsewhere.

Hello,

I fear you're right:

It's setting up an LVM volume which takes over 20 seconds, sometimes
more than 1 minute on my system when I run Linux 2.6.29-rcX... ; and no
problem with Linux <= 2.6.28.4 though.

I understand this is quite a vague description of the trouble, and I'm
considering more analysis in the near future.

This might be a Debian Lenny/Sid specific bug. I'm sorry for my
eagerness to fill in my initial bug report, because I wrongly considered
PadLock-related modules responsible for that delay.

> I guess this should be easy for others to reproduce.
>
> How long is the "long" delay?
>
> Please do this:
>
> add "log_buf_len=1M" to the kernel boot command line
> reboot
>
> dmesg -n 8
> modprobe padlock_aes &
> sleep 1
> echo t > /prog/sysrq-trigger
> dmesg -s 1000000 > foo
>
> and then send us `foo'. Pleas avoid wordwrapping it.
>
> This will permit us to see where `modprobe' is getting stuck.

No delay observed doing these commands ; I was wrong.

> Thanks.

Thanks too.

On the Debian Lenny/Sid average user point of view, it is still a
post-2.6.28 regression, though. Note: I only did comparisons between
different Pristine kernel versions.

But I am sorry not having more accurate clues about that trouble.

In hope my report will prove useful.

Sincerely,
Valentin QUEQUET