Re: [Xen-devel] Re: [Xen-users] 2.6.23 oops

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> > Is this similar to what you observed?
>
> That is exactly what I experienced. I tracked it down to:

Awesome!  Thanks for helping out here.

> xen_vcpuop_set_next_event(...)
>   ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single);

> always returns -ETIME

Which, AFAICS has the expected meaning that the requested time is in the past.

> resulting in a infinite loop in
> tick_setup_periodic(...)
> Where this never succeeds
>       if (!clockevents_program_event(dev, next, ktime_get()))
>                                  return;

in kernel/time/tick-common.c, right?

I see what you mean, but it's not immediately obvious to me what's going 
wrong.  I don't think the kernel mainline Xen uses even has clockevents, 
anyway, so I've not seen it before :-)

> Now my brain needs a rest. I never thought I had to go head first into
> the linux-kernel ;-) can't claim that I got any wiser ;-)

Every little helps.

Dip your head into tepid water just to forestall any overheating.

I may be able to take a look at this later tonight if Jeremy doesn't beat me 
to it.  I'd like to get a bit more familiar with our patches to mainline.

Cheers,
Mark

> > Cheers,
> > Mark
> >
> >> How far into the boot does it manage to get?  Has it started running
> >> userspace apps (the normal startup messages starting essential
> >> services), or is it still during the kernel initialisation?
> >>
> >> > Does anybody else see this:
> >>
> >> I've booted a kernel successfully on a UP AMD64 box with an SMP 2.6.23
> >> kernel, vcpus = 1 but I didn't bother giving it a virtual disk, so I
> >> don't know if userspace worked.  I'll give it a try shortly...
> >>
> >> Cheers,
> >> Mark
> >>
> >> > ------------[ cut here ]------------
> >> > kernel BUG at arch/i386/xen/multicalls.c:68!
> >> > invalid opcode: 0000 [#1]
> >> > SMP
> >> > CPU:    0
> >> > EIP:    0061:[<c01019a6>]    Not tainted VLI
> >> > EFLAGS: 00010002   (2.6.23 #26)
> >> > EIP is at xen_mc_flush+0xa6/0xb0
> >> > eax: 00000001   ebx: 00000003   ecx: 00000001   edx: c10c1060
> >> > esi: 00000000   edi: 00000001   ebp: c5c8d000   esp: c1101d28
> >> > ds: 007b   es: 007b   fs: 00d8  gs: 0000  ss: e021
> >> > Process swapper (pid: 1, ti=c1100000 task=c10eda90 task.ti=c1100000)
> >> > Stack: 000218ee c10c10a0 c10c1460 c0101ede c5c8ce40 c02b90e0 c10eda90
> >> > 00000000 c0101ff3 c5c8ce40 c015caca c5d3b49c 00000080 c5eadaa0
> >> > 00000000 c10eed80 c01584d0 c02b9a80 c5cfd560 c02a53d2 c1142440
> >> > c015c077 c1101d84 c5eadaa0 Call Trace:
> >> >   [<c0101ede>] xen_pgd_pin+0x9e/0x100
> >> >   [<c0101ff3>] xen_activate_mm+0x13/0x20
> >> >   [<c015caca>] flush_old_exec+0x3ca/0x7f0
> >> >   [<c01584d0>] do_sync_read+0x0/0x120
> >> >   [<c015c077>] kernel_read+0x37/0x50
> >> >   [<c018308e>] load_elf_binary+0x2fe/0x1af0
> >> >   [<c013ec27>] __alloc_pages+0x57/0x310
> >> >   [<c0155387>] kmem_cache_alloc+0x47/0x90
> >> >   [<c0147610>] handle_mm_fault+0x540/0x710
> >> >   [<c01585a5>] do_sync_read+0xd5/0x120
> >> >   [<c0145e10>] vm_normal_page+0x10/0x70
> >> >   [<c0145e10>] vm_normal_page+0x10/0x70
> >> >   [<c0146471>] follow_page+0xf1/0x170
> >> >   [<c01478ca>] get_user_pages+0xea/0x2e0
> >> >   [<c015bbe2>] get_arg_page+0x42/0xa0
> >> >   [<c015bdc6>] copy_strings+0x186/0x1a0
> >> >   [<c015be64>] search_binary_handler+0x54/0x110
> >> >   [<c015d83b>] do_execve+0x14b/0x170
> >> >   [<c010425f>] sys_execve+0x2f/0x90
> >> >   [<c0105c72>] syscall_call+0x7/0xb
> >> >   [<c010a364>] kernel_execve+0x14/0x20
> >> >   [<c0100173>] init_post+0xa3/0xf0
> >> >   [<c02d594f>] kernel_init+0x20f/0x310
> >> >   [<c0118464>] schedule_tail+0x34/0x90
> >> >   [<c0105b16>] ret_from_fork+0x6/0x20
> >> >   [<c0105c7b>] syscall_exit+0x5/0x1b
> >> >   [<c02d5740>] kernel_init+0x0/0x310
> >> >   [<c02d5740>] kernel_init+0x0/0x310
> >> >   [<c0106e77>] kernel_thread_helper+0x7/0x10
> >> >   =======================
> >
> > --
> > Dave: Just a question. What use is a unicyle with no seat?  And no
> > pedals! Mark: To answer a question with a question: What use is a
> > skateboard? Dave: Skateboards have wheels.
> > Mark: My wheel has a wheel!



-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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