[Xen-devel] Re: BUG: soft lockup detected on CPU#0! on 3.0.2-2

[john maclean <jayeola@xxxxxxxxx>]

Keir Fraser <Keir.Fraser <at> cl.cam.ac.uk> writes:

> 
> On 16/9/06 2:34 am, "Luke Crawford" <lsc <at> prgmr.com> wrote:
> 
> > completely unpingable.  console was also dead, nobody tried the xen
> > console.  (I just setup a better reboot procedure for my hosting company;
> > I need to setup something similar here so that we don't loose the data we
> > need to figure this out.)
> > 
> > Where should I start looking to find out exactly what "bug: soft lockup on
> > cpu0" means?  linux source/docs?  or Xen source/docs?
> 
> The watchdog code runs a kernel thread on every CPU. This is supposed to
> wake up every second and update a per-CPU counter. A hook from the timer
> interrupt checks the per-CPU counter and prints a softlockup warning if the
> counter is not updated for 10 seconds.
> 
> 3.0.2-2 is known to be susceptible to softlockups because the Xen scheduler
> will starve domains to run domain0. It's not clear if that's what is
> happening here, but you need to repro on tip of xen-3.0-testing to find out
> one way or the other. Because of the number of bug fixes since 3.0.2-3 we
> don't recommend running any old releases of 3.0.2.
> 
>  -- Keir
> 


I also get soft lockup warnings in my Xen domU. I'd really love to be able to
determine the source of the error(s) and perhaps fix them myself. Not a kernel
hacker and my C is rather flaky but can anyone point me to some docs one how ti
interpret data from:-

Pausing... 5<3>BUG: soft lockup detected on CPU#0!

Pid: 1, comm:                 init
EIP: 0061:[<c0107c64>] CPU: 0
EIP is at delay_tsc+0x14/0x20
 EFLAGS: 00000287    Not tainted  (2.6.16-xen #1)
 EAX: 79d31a46 EBX: 000c74e4 ECX: 79c788c9 EDX: 00004616
 ESI: 00000005 EDI: c0112520 EBP: bff6c010 DS: 007b ES: 007b
 CR0: 8005003b CR2: 431ea00c CR3: 003e3000 CR4: 00000640
  [<c011264d>] do_fixup_4gb_segment+0x12d/0x160
  [<c0113fa0>] do_page_fault+0x4a0/0x7ac
   [<c03de17c>] icmp_init+0xdc/0x110
 [<c03de284>] inet_init+0x74/0x380
[<c03de17c>] icmp_init+0xdc/0x110
[<c0105243>] error_code+0x2b/0x30
Continuing...

Are there any local docs, tools or dirs (on my machine) or URLs that anyone can
point me to?

 - jm



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