2006-05-16 20:50:22

by Ju, Seokmann

[permalink] [raw]
Subject: Help: strange messages from kernel on IA64 platform

Hi,

During communication in between application and megaraid driver via
IOCTL, the system displays messages which are not easy to track down.
Following is one of the messages and same messages with different values
are poping up regularly.
---
Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
---

I understand the kernel is complaining about the address which is not
aligned and, found the message is coming from function
'ia64_handle_unaligned()' in the arch/ia64/kernel/unaligned.c.
But, I couldn't find who is calling this function and further details of
reasons.

Where should I start to figure out it?

Thank you,

Seokmann


2006-05-16 21:00:17

by Chase Venters

[permalink] [raw]
Subject: Re: Help: strange messages from kernel on IA64 platform

On Tue, 16 May 2006, Ju, Seokmann wrote:

> Hi,
>
> During communication in between application and megaraid driver via
> IOCTL, the system displays messages which are not easy to track down.
> Following is one of the messages and same messages with different values
> are poping up regularly.
> ---
> Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
> ---
>
> I understand the kernel is complaining about the address which is not
> aligned and, found the message is coming from function
> 'ia64_handle_unaligned()' in the arch/ia64/kernel/unaligned.c.
> But, I couldn't find who is calling this function and further details of
> reasons.
>
> Where should I start to figure out it?

It's a trap, which means the CPU is effectively calling that function. My
best suggestion is to figure out what data is at 0xe00000007f3d80dc and
what instructions are at 0xa0000002000373b1.

> Thank you,
>
> Seokmann

Thanks,
Chase

2006-05-16 21:12:56

by Ju, Seokmann

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

Hi,

Tuesday, May 16, 2006 5:00 PM, Chase Venters wrote:
> It's a trap, which means the CPU is effectively calling that
> function.
O.K, that's why...
Then, Is there anyway to look up trap table that the CPU has?
> My best suggestion is to figure out what data is at
> 0xe00000007f3d80dc and
> what instructions are at 0xa0000002000373b1.
I will try as you suggested.
Thank you very much for comment.

Regards,

> -----Original Message-----
> From: Chase Venters [mailto:[email protected]]
> Sent: Tuesday, May 16, 2006 5:00 PM
> To: Ju, Seokmann
> Cc: Linux Kernel Mailing List; [email protected]
> Subject: Re: Help: strange messages from kernel on IA64 platform
>
> On Tue, 16 May 2006, Ju, Seokmann wrote:
>
> > Hi,
> >
> > During communication in between application and megaraid driver via
> > IOCTL, the system displays messages which are not easy to
> track down.
> > Following is one of the messages and same messages with
> different values
> > are poping up regularly.
> > ---
> > Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
> > ---
> >
> > I understand the kernel is complaining about the address
> which is not
> > aligned and, found the message is coming from function
> > 'ia64_handle_unaligned()' in the arch/ia64/kernel/unaligned.c.
> > But, I couldn't find who is calling this function and
> further details of
> > reasons.
> >
> > Where should I start to figure out it?
>
> It's a trap, which means the CPU is effectively calling that
> function. My
> best suggestion is to figure out what data is at
> 0xe00000007f3d80dc and
> what instructions are at 0xa0000002000373b1.
>
> > Thank you,
> >
> > Seokmann
>
> Thanks,
> Chase
>

2006-05-16 21:20:06

by Döhr, Markus ICC-H

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

> During communication in between application and megaraid
> driver via IOCTL, the system displays messages which are not
> easy to track down.
> Following is one of the messages and same messages with
> different values are poping up regularly.
> ---
> Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
> ---

We have this message too on our main database server; the interesting part
is, that the application, which triggers this error, is a database (MaxDB)
and the process name is "kernel"... Just to avoid confusion: look if there's
an application with such name running on your system.


Greetz,


SIEGENIA-AUBI KG
Informationswesen

i.A.

Markus D?hr
SAP-CC/BC, SAPDB-DBA

Tel.: +49 6503 917-152
Fax: +49 6503 917-7152
E-Mail: [email protected]
Internet: http://www.siegenia-aubi.com

2006-05-16 21:30:12

by Ju, Seokmann

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

Hi,

Tuesday, May 16, 2006 5:20 PM, "D?hr, Markus ICC-H" wrote:
> We have this message too on our main database server; the
> interesting part
> is, that the application, which triggers this error, is a
> database (MaxDB)
> and the process name is "kernel"... Just to avoid confusion:
> look if there's
> an application with such name running on your system.
I quickly looked at the system with 'ps' command.
It seems there is no such process which starting its name with "kernel.." on the system.
Thank you for your comment.

Regards,

> -----Original Message-----
> From: "D?hr, Markus ICC-H" [mailto:[email protected]]
> Sent: Tuesday, May 16, 2006 5:20 PM
> To: Ju, Seokmann; Linux Kernel Mailing List
> Cc: [email protected]
> Subject: RE: Help: strange messages from kernel on IA64 platform
>
> > During communication in between application and megaraid
> > driver via IOCTL, the system displays messages which are not
> > easy to track down.
> > Following is one of the messages and same messages with
> > different values are poping up regularly.
> > ---
> > Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
> > ---
>
> We have this message too on our main database server; the
> interesting part
> is, that the application, which triggers this error, is a
> database (MaxDB)
> and the process name is "kernel"... Just to avoid confusion:
> look if there's
> an application with such name running on your system.
>
>
> Greetz,
>
>
> SIEGENIA-AUBI KG
> Informationswesen
>
> i.A.
>
> Markus D?hr
> SAP-CC/BC, SAPDB-DBA
>
> Tel.: +49 6503 917-152
> Fax: +49 6503 917-7152
> E-Mail: [email protected]
> Internet: http://www.siegenia-aubi.com
>
>

2006-05-16 21:32:51

by Chen, Kenneth W

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

Ju, Seokmann wrote on Tuesday, May 16, 2006 2:13 PM
> Tuesday, May 16, 2006 5:00 PM, Chase Venters wrote:
> > It's a trap, which means the CPU is effectively calling that
> function.
> O.K, that's why...
> Then, Is there anyway to look up trap table that the CPU has?

By looking at the instruction address that triggered the unaligned
fault, it is coming from a kernel module.

You should look at the runtime symbol table /proc/kallsyms and try
to map that ip into a function.

- Ken

2006-05-16 21:38:49

by Chen, Kenneth W

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

D?hr, Markus ICC-H wrote on Tuesday, May 16, 2006 2:20 PM
> > During communication in between application and megaraid
> > driver via IOCTL, the system displays messages which are not
> > easy to track down.
> > Following is one of the messages and same messages with
> > different values are poping up regularly.
> > ---
> > Kernel unaligned access to 0xe00000007f3d80dc ip=0xa0000002000373b1
> > ---
>
> We have this message too on our main database server; the interesting part
> is, that the application, which triggers this error, is a database (MaxDB)
> and the process name is "kernel"... Just to avoid confusion: look if there's
> an application with such name running on your system.

Unaligned access warning for user space process will print in a slightly
different format. It will print process name and its pid, something like:

cgc(15270): unaligned access to 0x20000000002b8025, ip=0x4000000000000b21

(you can also make the differentiation by looking at the data and instruction
address).

- Ken

2006-05-17 01:09:00

by Peter Chubb

[permalink] [raw]
Subject: RE: Help: strange messages from kernel on IA64 platform

>>>>> "Kenneth" == Kenneth W Chen <Chen> writes:

Kenneth> Ju, Seokmann wrote on Tuesday, May 16, 2006 2:13 PM
>> Tuesday, May 16, 2006 5:00 PM, Chase Venters wrote: > It's a trap,
>> which means the CPU is effectively calling that function. O.K,
>> that's why... Then, Is there anyway to look up trap table that the
>> CPU has?

Kenneth> By looking at the instruction address that triggered the
Kenneth> unaligned fault, it is coming from a kernel module.

General details for tracking down unaligned access problems in IA64
linux at http://www.gelato.unsw.edu.au/IA64wiki/UnalignedAccesses
--
Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au
http://www.ertos.nicta.com.au ERTOS within National ICT Australia