Subject: Re: kernel: alignment fault trap on sparc
To: Manuel Bouyer <>
From: Eduardo Horvath <>
List: tech-kern
Date: 06/07/2004 18:26:38
On Mon, Jun 07, 2004 at 07:57:25PM +0200, Manuel Bouyer wrote:
> On Sat, Jun 05, 2004 at 07:16:25PM +0000, Eduardo Horvath wrote:
> > > No idea how this instruction could cause an alignment trap.
> > 
> > sethi %hi(0xf02e3000), %l6 cannot generate an alignment fault.  Only loads or 
> > stores or possibly some sort of branches can generate alignment faults.
> > 
> > You can try disassembling a few instructions surrounding the one that allegedly
> > caused the trap and see if one of them was the real culprit.  
> How can I do that ??I didn't find anything in ddb to do disassembly, but I
> probably missed something.


(Or man ddb.)

> > Otherwise, it could be that the instruction in the instruction cache does not
> > match the contents in memory,
> Software bug ? we have had cache issues on sun4c in the past ...

Could be cache coherency issues.

> > or your CPU is getting old and flakey.  I've seen
> > this happen a lot with old machines.
> I didn't have much problems with sparc yet. And this box started doing this
> right after the upgrade, it was solid under 1.6.2.

Could be a coincidence that the hardware broke at around the same time you
updated the software.  I've seen that happen on occasion.

In any case, you need a proper crashdump analysis.