Re: [LKML] [PATCH] Fix NULL pointer for Xen guests
From: Prarit Bhargava
Date: Tue Apr 27 2010 - 14:47:38 EST
On 04/27/2010 02:34 PM, Konrad Rzeszutek Wilk wrote:
Can you provide a short example of test scenario? As in what I should do
to reproduce this problem?
Take the latest upstream (well ... to be honest, a bit older than that
because of some other bugs) -- take 2.6.33 and try to boot it as a PV
2.6.34-rc5 PV boots under Xen for me (and pretty much since 2.6.33 +
Suresh fix for the CONFIG_RODATA_MARK).
Perhaps I am missing some of the .config options you have set that make it not work?
The irqbalance daemon looks to be running - but I think you are hitting
this during bootup? How long do you have to wait for this to trigger?
It happens during bootup. I don't have a 2.6.33 vanilla panic handy
but I do have one from an earlier 2.6.32...
rip: ffffffff81256f45 delay_tsc+0x45
rsp: ffff8800fac95a98
rax: fffffffff6ef46d0 rbx: 00000002 rcx: f6ef46d0 rdx: 0010850c
rsi: 002b3bb6 rdi: 002b3bcc rbp: ffff8800fac95ab8
r8: ffffffff r9: 00000002 r10: 00000002 r11: 00000000
r12: fffffffff6dec1c4 r13: 00000002 r14: 002b3bcc r15: 00000001
cs: 0000e033 ds: 00000000 fs: 00000000 gs: 00000000
Stack:
000000000002ef45 ffff8800fac95c88 0000000000000009 ffff8800fac93540
ffff8800fac95ac8 ffffffff81256ef6 ffff8800fac95b48 ffffffff814c6341
0000000000000010 ffff8800fac95b38 ffff880000000008 ffff8800fac95b58
ffff8800fac95b08 a22d306b065d4a66 0000000000000000 0000000000000000
Code:
f3 90 65 8b 1c 25 d8 e3 00 00 44 39 eb 75 23 66 66 90 0f ae e8<e8> 46 3d dc ff
66 90 48 98 48 89
Call Trace:
[<ffffffff81256f45>] delay_tsc+0x45<--
[<ffffffff81256ef6>] __const_udelay+0x46
[<ffffffff814c6341>] panic+0x135
[<ffffffff814ca23c>] oops_end+0xdc
[<ffffffff81042272>] no_context+0xf2
[<ffffffff8125946c>] __bitmap_weight+0x8c
[<ffffffff81042505>] __bad_area_nosemaphore+0x125
[<ffffffff8105fad4>] find_busiest_group+0x254
[<ffffffff810425d3>] bad_area_nosemaphore+0x13
[<ffffffff814cbccf>] do_page_fault+0x2ef
[<ffffffff814c9595>] page_fault+0x25
[<ffffffff810302f2>] irq_force_complete_move+0x12
[<ffffffff81015214>] fixup_irqs+0xa4
[<ffffffff8102ce59>] cpu_disable_common+0x1a9
[<ffffffff8100f9c2>] check_events+0x12
[<ffffffff810c2550>] __stop_machine+0x120
[<ffffffff8100ff75>] xen_cpu_disable+0x25
[<ffffffff814b0427>] take_cpu_down+0x17
[<ffffffff810c25f9>] stop_cpu+0xa9
[<ffffffff8108869d>] worker_thread+0x16d
[<ffffffff8100f19d>] xen_force_evtchn_callback+0xd
[<ffffffff8108dd00>] wake_up_bit+0x40
[<ffffffff814c90f6>] _spin_unlock_irqrestore+0x16
[<ffffffff81088530>] create_workqueue_thread+0xd0
[<ffffffff8108d9a6>] kthread+0x96
[<ffffffff8101418a>] child_rip+0xa
[<ffffffff81013351>] int_ret_from_sys_call+0x7
[<ffffffff81013add>] retint_restore_args+0x5
[<ffffffff81014180>] kernel_thread+0xe0
How many CPUs did you assign to your guest?
It didn't matter as long as vcpus >1 and maxcpus > vcpus.
What are the "other bugs" you speak off?
I got a different panic (which I've yet to resolve).
guest. I'm using a RHEL5 Xen HV fwiw ...
OK, so your control domain is RHEL5. Mine is the Jeremy's xen/next one
(2.6.32). Let me try to compile RHEL5 under FC11 - any tricks necessary
to do that?
I haven't tried it -- it might work :)
Also, did you try booting with maxvcpus > vcpus as drjones suggested ?
P.
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