Re: post 2.6.7 BK change breaks Java?

[Brian Gerst]

Jesper Juhl wrote:
> On Sun, 11 Jul 2004, Brian Gerst wrote:
>
>
> > Brian Gerst wrote:
> >
> > > Jesper Juhl wrote:
> > >
> > >
> > > > On Sun, 11 Jul 2004, Jesper Juhl wrote:
> > > >
> > > >
> > > >
> > > > > On Sun, 11 Jul 2004, Grzegorz Kulewski wrote:
> > > > >
> > > > >
> > > > >
> > > > > > On Sun, 11 Jul 2004, Jesper Juhl wrote:
> > > > > >
> > > > > >
> > > > > >
> > > > > > > On Fri, 9 Jul 2004, Jesper Juhl wrote:
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > > On Fri, 9 Jul 2004, Con Kolivas wrote:
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > > but I suspect it's one of those possibly interfering. Looking at the
> > > > > > > > > patches in question I have no idea how they could do it. I guess
> > > > > > > > > if you
> > > > > > > > > can try backing them out it would be helpful. Here are links to the
> > > > > > > > > patches in question.
> > > > > > > > > http://ck.kolivas.org/patches/2.6/2.6.7/2.6.7-ck5/split-out/1100_ip_tabl
> > > > > > > > >
> > > > > > > > > es.patch
> > > > > > > > > http://ck.kolivas.org/patches/2.6/2.6.7/2.6.7-ck5/split-out/1105_CAN-200
> > > > > > > > >
> > > > > > > > > 4-0497.patch
> > > > > > > > > http://ck.kolivas.org/patches/2.6/2.6.7/2.6.7-ck5/split-out/1110_proc.pa
> > > > > > > > >
> > > > > > > > > tch
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks Con, I'll try playing with those tomorrow (got no time
> > > > > > > > tonight),
> > > > > > > > and report back.
> > > > > > >
> > > > > > > Ok, got them all 3 backed out of 2.6.7-mm7 , but that doesn't change a
> > > > > > > thing. The JVM still dies when I try to run eclipse.
> > > > > >
> > > > > >
> > > > > > I can run Eclipse without any problems on 2.6.7-bk20-ck5 + few other
> > > > > > not
> > > > > > related patches. Maybe try using non -mm? Try 2.6.7-bk20 and then try
> > > > > > reverting some patches. Maybe there is some other problem in -mm that
> > > > > > gives similar results?
> > > > >
> > > > > with plain 2.6.7-bk20 I see the issue, same with 2.6.7-mm7. Reverting
> > > > > http://linux.bkbits.net:8080/linux-2.6/cset@xxxxxx from -mm7 fixes the
> > > > > issue. I'm currently building 2.6.7-bk20 minus that cset and I'll report
> > > > > back on the results of that in a few minutes.
> > > >
> > > > 2.6.7-bk20 minus the cset works.
> > > >
> > > > Testing with 2.6.8-rc1 and backing out one or both of the changes in the
> > > > cset I get these results :
> > > > 2.6.8-rc1       - vanilla                                       -
> > > > breaks Java
> > > > 2.6.8-rc1-jju1  - both changes backed out                       - works
> > > > 2.6.8-rc1-jju2  - only first change (sys_rt_sigsuspend) applied - works
> > > > 2.6.8-rc1-jju3  - only second change (sys_sigaltstack) applied  -
> > > > breaks Java
> > > >
> > > > --
> > > > Jesper Juhl <juhl-lkml@xxxxxx>
> > >
> > >
> > > Looks like a GCC (gcc version 3.4.1 20040702 (Red Hat Linux 3.4.1-2))
> > > screwup:
> > >
> > > sys_sigaltstack:
> > >        movl    4(%esp), %eax
> > >        movl    8(%esp), %edx
> > >        movl    56(%esp), %ecx
> > >        jmp     do_sigaltstack
> > >
> > > The offsets should be 4 more, to account for the return address on the
> > > stack.
> >
> > Nevermind, I should have looked more carefully.  The offsets are fine in
> > my example.  What version of GCC are you using?
>
> gcc 3.4.0
>
> I got a patch from Linus yesterday that seems to fix it nicely on top of
> 2.6.8-rc1. I guess he has his reasons for not CC'ing it to the list, but
> I've given him feedback on my testing of it, so I hope it'll surface as
> soon as he's happy with it.

I see Linus commited a changeset that avoids a tailcall from this 
function, which messes up the stack if CONFIG_REGPARM=n.  Specifically, 
it clobbers %edx in the pt_regs image:

sys_sigaltstack:
        movl    56(%esp), %eax
        movl    %eax, 12(%esp)
        jmp     do_sigaltstack

--
				Brian Gerst
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