Hey Remek,
It may take a little while to show up on bugs.opensolaris.org, but the bug
has been filed, and I'll try to get a fix in place in a month or two.
Adam
On Wed, Oct 22, 2008 at 02:26:02PM +0200, P. Remek wrote:
> Hi Adam,
>
> I've searched for issue number 6762246 but I can't see it.
> Anyway, if you would need anything else like bugfix verification
> or something, let me know.
>
> Remek
>
> On Wed, Oct 22, 2008 at 5:00 AM, Adam Leventhal <[EMAIL PROTECTED]> wrote:
> > Hey Remek,
> >
> > Thanks for working me offline to gather the data I needed to understand
> > this issue. You're hitting a rather interesting issue in that this function
> > (log_vwrite) contains both a jump table (something that puts the pid
> > provider's return site detection code into a very conservative mode) and
> > tail-calls (relatively rare in 32-bit x86. In particular, check out this
> > sequence:
> >
> > _Z10log_vwriteiPKcPc+0xb2: popl %ebx
> > _Z10log_vwriteiPKcPc+0xb3: popl %esi
> > _Z10log_vwriteiPKcPc+0xb4: popl %edi
> > _Z10log_vwriteiPKcPc+0xb5: leave
> > _Z10log_vwriteiPKcPc+0xb6: jmp -0xef06 <fatal>
> >
> > Normally, we'd detect this as a return site, but the presence of the jump
> > table elswhere in the function has put us into a case where we don't detect
> > that specific instruction sequence. We should add that code sequence to our
> > short list.
> >
> > I've filed the following bug for you:
> >
> > 6762246 when jump tables fight tail-calls no one wins
> >
> > Adam
> >
> >
> > On Mon, Oct 20, 2008 at 05:33:03PM +0200, P. Remek wrote:
> >> Hi,
> >>
> >> I am using pid provider and I have noticed that return probe is not fired
> >> when
> >> leaving function with variable number of arguments using va_start and
> >> va_stop.
> >> Having such code:
> >>
> >> log() {
> >> va_start(ap, fmt);
> >> log_vwrite(l, fmt, ap);
> >> va_end(ap);
> >> }
> >>
> >> I get such output from dtrace:
> >>
> >> -> log
> >> -> log_vwrite
> >> <- log
> >>
> >>
> >> Is this a dtrace problem or is there some general problem why it can't work
> >> when using variable argument lists?
> >>
> >> Thanks,
> >> Remek
> >> _______________________________________________
> >> dtrace-discuss mailing list
> >> dtrace-discuss@opensolaris.org
> >
> > --
> > Adam Leventhal, Fishworks http://blogs.sun.com/ahl
> >
--
Adam Leventhal, Fishworks http://blogs.sun.com/ahl
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