[Linux-ia64] Re: Fault 26?

[Linux-ia64] Re: Fault 26?

[Bill Nottingham]

Bill Nottingham (notting@redhat.com) said: 
> >   Bill> What is fault type 26?  I'm getting a few of these recently.
> > 
> > It's the "NaT consumption fault".  Either buggy code is trying to eat
> > a NaT value or something else goes wrong and a NaT value is created
> > when it shouldn't be.
> 
> Hm. We're getting it (in cpp) when building the kernel.

Also occasionally in ld, rpm, find, etc.

Bill

[Linux-ia64] Re: Fault 26?

[Bill Nottingham]

David Mosberger (davidm@hpl.hp.com) said: 
>   Bill> What is fault type 26?  I'm getting a few of these recently.
> 
> It's the "NaT consumption fault".  Either buggy code is trying to eat
> a NaT value or something else goes wrong and a NaT value is created
> when it shouldn't be.

It's happening in strcpy(), of all places, with two seemingly valid
arguments.

Bill

Re: [Linux-ia64] Re: Fault 26?

[Dan Pop]

On Wed, 6 Dec 2000, Bill Nottingham wrote:

> David Mosberger (davidm@hpl.hp.com) said: 
> >   Bill> What is fault type 26?  I'm getting a few of these recently.
> > 
> > It's the "NaT consumption fault".  Either buggy code is trying to eat
> > a NaT value or something else goes wrong and a NaT value is created
> > when it shouldn't be.
> 
> It's happening in strcpy(), of all places, with two seemingly valid
> arguments.

Here's a patch that should fix it.  The bug was in a recovery code
that was highly unlikely to be ever executed, hence it passed
unnoticed for so long :-)

2000-12-07  Dan Pop  <Dan.Pop@cern.ch>

        * sysdeps/ia64/strcpy.S: fix a bug in a recovery code sequence


--- strcpy.S.old	Thu Dec  7 05:10:17 2000
+++ strcpy.S	Thu Dec  7 05:11:20 2000
@@ -120,7 +120,7 @@
 	br.ret.sptk.many b0
 .recovery2:
 	add	tmp = -8, asrc ;;
-	ld8	r[MEMLAT] = [tmp]
+	ld8	r[0] = [tmp]
 	br.cond.sptk .back2
 .recovery3:
 	add	tmp = -(MEMLAT + 1) * 8, src ;;


Thanks to David Mosberger for investigating the problem.

Dan

Re: [Linux-ia64] Re: Fault 26?

[David Mosberger]

>>>>> On Thu, 7 Dec 2000 05:32:41 +0100 (MET), Dan Pop <Dan.Pop@cern.ch> said:

  Dan> Thanks to David Mosberger for investigating the problem.

Bill did all the hard work, actually.

Thanks for the fix!

	--david

Re: [Linux-ia64] Re: Fault 26?

[Jes Sorensen]

>>>>> "Dan" = Dan Pop <Dan.Pop@cern.ch> writes:

Dan> On Wed, 6 Dec 2000, Bill Nottingham wrote:

>> David Mosberger (davidm@hpl.hp.com) said: > Bill> What is fault
>> type 26?  I'm getting a few of these recently.  > > It's the "NaT
>> consumption fault".  Either buggy code is trying to eat > a NaT
>> value or something else goes wrong and a NaT value is created >
>> when it shouldn't be.
>> 
>> It's happening in strcpy(), of all places, with two seemingly valid
>> arguments.

Dan> Here's a patch that should fix it.  The bug was in a recovery
Dan> code that was highly unlikely to be ever executed, hence it
Dan> passed unnoticed for so long :-)

Great

I have applied this to my tree and asked Ulrich to apply it to the
official tree.

Jes