[Xen-devel] Re: Cannot boot xen DomU > 2.6.23.1

[xming <xmingske@xxxxxxxxx>]

> OK, I misunderstood your original report to mean that something was
> complaining about "too much" output.  You're saying that lots of console
> output seems to lock the domain.

Sorry about that, and yes that is the case.

> I've had a report about heavy disk IO seems to lock up as well.  Perhaps
> they're both related to high event rates.  Do you think you could try an
> IO-intensive workload to see if you can get a similar lockup?

IO-intensive locks up too (see below)

> When the domain is locked up, what does /usr/lib/xen/bin/xenctx say?

see below

> Hm.  Rather than backing out the structure-change patch, could you try
> this workaround:
>
> diff -r be3ca4e0e19e arch/x86/xen/enlighten.c
> --- a/arch/x86/xen/enlighten.c  Thu Jan 17 14:25:07 2008 -0800
> +++ b/arch/x86/xen/enlighten.c  Thu Jan 17 16:37:42 2008 -0800
> @@ -95,7 +95,7 @@ struct shared_info *HYPERVISOR_shared_in
>   *
>   * 0: not available, 1: available
>   */
> -static int have_vcpu_info_placement = 1;
> +static int have_vcpu_info_placement = 0;
>
>  static void __init xen_vcpu_setup(int cpu)
>  {

First of all this patch solves the lock-ups, it works as advertised :) The DomU
works as before. Just for the record for people trying to apply this to 2.6.23.x
you need to change the /x86/ to /i386/, unified x86 is since 2.6.24.

I tried to create 2 tests, one is IO intensive and the other is console
output intensive:

test1. bonnie++ -s 1024 -u nobody
test2. for i in `seq 1 50000`; do echo 00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ; done

In all acese where it crashed(hanged) there was no oops/panic.

scenario 1 (booted 2.6.23.14 as is)
--------------------------------------------------
(but with init=/bin/bash, otherwise I couldn't get a prompt)

test1: crashed

# /usr/lib/xen/bin/xenctx 108
eip: c037c0c7
esp: c0343f90
eax: 00000000   ebx: 00000001   ecx: 00000000   edx: c0342000
esi: c0373004   edi: c1210df4   ebp: 00001b7d
 cs: 00000061    ds: 0000007b    fs: 000000d8    gs: 00000000

Stack:
 c0100add c0378980 c0101962 c0104821 c120a000 c0378df4 c0348cff 00000025
 c0348430 00000004 00009000 00006df4 00ea1000 c0363be0 c0343fe8 c03dd007
 00000000 c0343fec c0349868 c0343fe0 178bc1f1 00002001 01020800 00060fb1
 00000000 c03dd000 00000000 00000000

Code:
cc cc cc cc cc cc cc cc cc cc cc cc cc cc b8 06 00 00 00 cd 82 <c3> cc
cc cc cc cc cc cc cc cc cc

Call Trace:
  [<c037c0c7>]  <--
  [<c0100add>]
  [<c0378980>]
  [<c0101962>]
  [<c0104821>]
  [<c120a000>]
  [<c0378df4>]
  [<c0348cff>]
  [<c0348430>]
  [<c0363be0>]
  [<c0343fe8>]
  [<c03dd007>]
  [<c0343fec>]
  [<c0349868>]
  [<c0343fe0>]
  [<178bc1f1>]
  [<c03dd000>]

test2: crashed after many many retries and sometimes with strange output

00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAA
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
0000AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ

# /usr/lib/xen/bin/xenctx 113
eip: c037c0c7
esp: c0343f90
eax: 00000000   ebx: 00000001   ecx: 00000000   edx: c0342000
esi: c0373004   edi: c1210df4   ebp: 00001b7d
 cs: 00000061    ds: 0000007b    fs: 000000d8    gs: 00000000

Stack:
 c0100add c0378980 c0101962 c0104821 c120a000 c0378df4 c0348cff 00000025
 c0348430 00000004 00009000 00006df4 00ea1000 c0363be0 c0343fe8 c03dd007
 00000000 c0343fec c0349868 c0343fe0 178bc1f1 00002001 00020800 00060fb1
 00000000 c03dd000 00000000 00000000

Code:
cc cc cc cc cc cc cc cc cc cc cc cc cc cc b8 06 00 00 00 cd 82 <c3> cc
cc cc cc cc cc cc cc cc cc

Call Trace:
  [<c037c0c7>]  <--
  [<c0100add>]
  [<c0378980>]
  [<c0101962>]
  [<c0104821>]
  [<c120a000>]
  [<c0378df4>]
  [<c0348cff>]
  [<c0348430>]
  [<c0363be0>]
  [<c0343fe8>]
  [<c03dd007>]
  [<c0343fec>]
  [<c0349868>]
  [<c0343fe0>]
  [<178bc1f1>]
  [<c03dd000>]

Scenario 2 (have_vcpu_info_placement = 0)
--------------------------------------------------------------

test1: no crash
test2: no crash, but occationally I still get funny output like this

00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
0000AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
000AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
000AAAAAAAAAAAAAAAAAAAAAAAAAAZZ
00AAAAAAAAAAAAAAAAAAAAAAAAAAZZ

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