Re: IP auto-config with DHCP on sparc64 possibly broken

[Frank Scheiner]

On 02/19/2018 08:44 AM, John Paul Adrian Glaubitz wrote:

On 02/18/2018 10:40 PM, Frank Scheiner wrote:

, it's just that
the tool you are using is apparently producing unaligned accesses.


What you emphasized is from the AlphaServer DS25, do you assume that unaligned 
accesses lead to bus errors on sparc64?


To be honest, you wrote so much text that I didn't notice you were
talking about an Alpha machine here.


Yeak, sorry, but according to what I read so far you still were on the 
right track with the unaligned accesses. There seem to be a few options 
to react on those, e.g. just print an info message, info message plus 
fix in software (which is slow) or send a SIGBUS to the causing process.


Why the behavior differs between different architectures is the 
question. I wouldn't mind a slowdown during operation of `ipconfig`, as 
it only happens on startup, but it might be substantial if applied to 
all compiled stuff for sparc64. On the other hand it looks like it's 
done exactly like that on alpha, if you consider the "mass" of unaligned 
trap messages there.


Cheers,
Frank

Re: IP auto-config with DHCP on sparc64 possibly broken

[John Paul Adrian Glaubitz]

On 02/18/2018 10:40 PM, Frank Scheiner wrote:
>> , it's just that
>> the tool you are using is apparently producing unaligned accesses.
> 
> What you emphasized is from the AlphaServer DS25, do you assume that 
> unaligned accesses lead to bus errors on sparc64?

To be honest, you wrote so much text that I didn't notice you were
talking about an Alpha machine here.

If you're talking about a command crashing, it would be enough to just
show the reproducer command line and then someone can have a look with
GDB to find the place where the unaligned access happens.

So, please try to reduce messages in such cases a bit so that we don't
have to search the important information in a wall of text.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaub...@debian.org
`. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
  `-GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: IP auto-config with DHCP on sparc64 possibly broken

[Frank Scheiner]

On 02/18/2018 10:48 PM, James Clarke wrote:

Having said that if there are unaligned
accesses reported on alpha then those are likely to also happen on sparc64 and
be the critters we're looking for.


Why do these only trap to software on alpha and not on sparc64? Is that 
due to a compiler option?


Cheers,
Frank

Re: IP auto-config with DHCP on sparc64 possibly broken

[James Clarke]

On 18 Feb 2018, at 21:34, John Paul Adrian Glaubitz 
 wrote:
> On 02/18/2018 10:10 PM, John Paul Adrian Glaubitz wrote:
>> See my emphasis above. It's not that the network stack is broken, it's just 
>> that
>> the tool you are using is apparently producing unaligned accesses.
>> 
>> Did you try running systemd-networkd?
> 
> As a quick shot into the dark, I have triggered a binNMU of src:klibc, maybe
> it was broken by binutils which recently suffered from issues on sparc64.

Which will (or should) be rejected by mini-dak, as my 2.0.4-11+sparc64.1 is in
unreleased (#885852 hasn't been fixed yet or even acknowledged by anyone). I'd
be surprised if it's the binutils bug, but I guess you could do a rebuild
locally and upload a .2 to unreleased. Having said that if there are unaligned
accesses reported on alpha then those are likely to also happen on sparc64 and
be the critters we're looking for.

James

Re: IP auto-config with DHCP on sparc64 possibly broken

[Frank Scheiner]

On 02/18/2018 10:10 PM, John Paul Adrian Glaubitz wrote:

IP-Config: no response after 3 s[    7.950191] ipconfig(196): unaligned trap at 
000120003868: 00011ffcf3af 28 2
[    8.058589] ipconfig(196): unaligned trap at 000120003868: 
00011ffcf3af 28 2

 ^^

(...)
Any idea what could be wrong with `ipconfig` or how I can further debug this?


See my emphasis above. It's not that the network stack is broken


Yeah, I should have been more specific in the subject, it's `ipconfig` 
or some dependency of it that looks broken.



, it's just that
the tool you are using is apparently producing unaligned accesses.


What you emphasized is from the AlphaServer DS25, do you assume that 
unaligned accesses lead to bus errors on sparc64?




Did you try running systemd-networkd?


No, but I also don't know how to include this in a Debian initramfs.

Cheers,
Frank

Re: IP auto-config with DHCP on sparc64 possibly broken

[John Paul Adrian Glaubitz]

On 02/18/2018 10:10 PM, John Paul Adrian Glaubitz wrote:
> See my emphasis above. It's not that the network stack is broken, it's just 
> that
> the tool you are using is apparently producing unaligned accesses.
> 
> Did you try running systemd-networkd?

As a quick shot into the dark, I have triggered a binNMU of src:klibc, maybe
it was broken by binutils which recently suffered from issues on sparc64.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaub...@debian.org
`. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
  `-GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: IP auto-config with DHCP on sparc64 possibly broken

[John Paul Adrian Glaubitz]

On 02/18/2018 09:55 PM, Frank Scheiner wrote:
> I'm currently working on creating a useful configuration for network boot 
> with GRUB2 on sparc64. But I'm experiencing problems during IP 
> auto-configuration.
> This is done by using the `ip=[...]` kernel command line option and the 
> `ipconfig` tool ([1]) included in the initramfs which evaluates this option.
> (...)
> Hence I currently do all needed configuration on sparc64 "manually" by 
> providing all required addresses in the `ip=[...]` option which at least 
> works but of
> course duplicates configuration. Other architectures (ppc64, alpha, hppa) 
> don't have this problem AFAICS.
> (...)
> IP-Config: no response after 3 s[    7.950191] ipconfig(196): unaligned trap 
> at 000120003868: 00011ffcf3af 28 2
> [    8.058589] ipconfig(196): unaligned trap at 000120003868: 
> 00011ffcf3af 28 2
^^
> (...)
> Any idea what could be wrong with `ipconfig` or how I can further debug this?

See my emphasis above. It's not that the network stack is broken, it's just that
the tool you are using is apparently producing unaligned accesses.

Did you try running systemd-networkd?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaub...@debian.org
`. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
  `-GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913