Re: [Xen-devel] sedf scheduler may cause a CPU fatal trap

[Guillaume Thouvenin <guillaume.thouvenin@xxxxxxx>]

On Fri, 13 Jan 2006 10:10:59 +0000
Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> wrote:

> On 13 Jan 2006, at 09:59, Guillaume Thouvenin wrote:
> 
> > I ran two commands on the xen-unstable.hg that produced the CPU fatal
> > trap. I tested the changset 8571 on a x86_64 xeon bi-processors with HT
> > enabled. I only started one unprivileged domain. The two commands are:
> >
> >    # xm sched-sedf 1 20000000 5000000 0 0 0
> >    # xm sched-sedf 1 20000000 0 0 1 0
> 
> There's a changeset (8577) queued up in our staging tree that should 
> hopefully fix this.

I tested the last Changeset (8717) and the CPU0 FATAL TRAP is always
present. I paste the message generated by Xen at the end of this email. I
can reproduce the bug easily (just run the two xm commands). 

Hope this help,
Guillaume. 

(XEN) CPU:    0
(XEN) RIP:    e010:[<ffff83000011e108>] desched_extra_dom+0x1c3/0x38a
(XEN) RFLAGS: 0000000000010006   CONTEXT: hypervisor
(XEN) rax: 00000004c4b40000   rbx: ffff830000fe5e80   rcx: ffff830000fe5e80
(XEN) rdx: 0000000000000000   rsi: 0000000000000001   rdi: ffff830000fbe080
(XEN) rbp: ffff8300001ebda8   rsp: ffff8300001ebd50   r8:  00000000deadbeef
(XEN) r9:  00000000deadbeef   r10: ffff8300001ebf28   r11: 0000000000000246
(XEN) r12: 0000000000000000   r13: 0000000000000000   r14: 0000000000000000
(XEN) r15: 0000000000000000   cr0: 000000008005003b   cr3: 0000000087f4c000
(XEN) (file=extable.c, line=77) Pre-exception: ffff83000011e108 -> 
0000000000000000
(XEN) Xen stack trace from rsp=ffff8300001ebd68:
(XEN)    CPU:    1
(XEN) RIP:    e010:[<ffff83000011e108>]ffff8300001ebdc0  
desched_extra_dom+0x1c3/0x38affff830000fe5e80
(XEN) RFLAGS: 0000000000010006   CONTEXT: hypervisor
(XEN) 0000000000020000 rax: 00000004c4b40000   rbx: ffff830000fe4d00   rcx: 
ffff830000fe4d00
(XEN) 00000001001ebdc0 rdx: 0000000000000000   rsi: 0000000000000001   rdi: 
ffff830000fc4080
(XEN)
(XEN)    rbp: ffff83000024fda8   rsp: ffff83000024fd50   r8:  00000000deadbeef
(XEN) ffff830000fe5e80 r9:  00000000deadbeef   r10: ffff83000024ff28   r11: 
0000000000000246
(XEN) ffff830000fbe080 r12: ffffffff8010002c   r13: 00000000ffffffff   r14: 
0000ffffffff8010
(XEN) 000000404424e250 r15: ffffffff803adfb0   cr0: 000000008005003b   cr3: 
0000000087f4e000
(XEN) ffff8300001f4380 Xen stack trace from rsp=ffff83000024fd68:
(XEN)
(XEN)    ffff8300001ebe38 ffff83000024fdc0 ffff83000011e6c3 ffff830000fe4d00 
ffff8300001f4380 000000000002
0000 0000000000000000 000000010024fdc0
(XEN)
(XEN)    ffff830000fe4d00 ffff8300001ebde8 ffff830000fc4080 ffff830000123c60 
000000406cad42ff 000000000000
0001 ffff8300001f4380 0000000000000000
(XEN)
(XEN)    ffff8300001ebe08 ffff83000024fe38 ffff830000123c16 ffff83000011e6c3 
ffff830000241fa0 ffff8300001f
4400 ffff830000241fb0 0000000000000000
(XEN)
(XEN)    ffff8300001ebe38 ffff83000024fde8 ffff830000fe5e80 ffff830000123c60 
ffff830000241f90 000000000000
0002 ffff830000241f80 0000000100000000
(XEN)
(XEN)    ffff83000024fe08 0000000000214280 ffff830000123c16 000000404424e250 
ffff830000ffaea0 ffff8300001e
bea8 ffff830000ffaeb0 ffff8300001217ae
(XEN)
(XEN)    ffff83000024fe38 0000000000000000 ffff830000fe4d00 ffff8300001ebe58 
ffff830000ffae90 aaaaaaaaaaaa
aaaa ffff830000ffae80 aaaaaaaaaaaaaaaa
(XEN)    0000000100214300
(XEN)    aaaaaaaaaaaaaaaa 000000406cad42ff aaaaaaaaaaaaaaaa ffff83000024fea8 
000000404424e250 ffff83000012
17ae
(XEN)    0000000000ffaf80 0000000000000000
(XEN)    0000000000000000 ffff83000024fe58 ffff830000fbe080 aaaaaaaaaaaaaaaa 
ffff830000fbe0f8 aaaaaaaaaaaa
aaaa ffff830000fbe080
(XEN)
(XEN)    ffff8300001ebec8 aaaaaaaaaaaaaaaa ffff8300001212e5 aaaaaaaaaaaaaaaa 
ffff8300001ebee8 000000406cad
42ff ffff830000fbe080 0000000100ffbd00
(XEN)    ffff8300001ebf08
(XEN)    0000000000000000 ffff8300001213a2 ffff830000fc4080 00000040bd20b201 
ffff830000fc40f8 0000000100fb
e0a0 ffff830000fc4080
(XEN)    0000000000000000
(XEN)    ffff83000024fec8 0000000000000000 ffff8300001212e5 00000001deadbeef 
ffff83000024fee8 ffff830000fb
e080 ffff830000fc4080
(XEN)
(XEN)    ffff83000024ff08 00007cffffe140b7 ffff8300001213a2 ffff830000159260 
000000408a76b981 ffffffff8010
d0ca 0000000100fc40a0 0000000000000006
(XEN)
(XEN)    0000000000000000 0000000000000000 0000000000000000 0000000000000000 
0000000000000000 00000001dead
beef 0000000000000000 ffff830000fc4080
(XEN)    0000000000000000
(XEN)    00007cffffdb00b7 0000000000000000 ffff830000159260 0000000000000246 
ffffffff8010d0ca 000000000000
0004 0000000000000006
(XEN)
(XEN)    ffffffff803adfb0 00000000ffffac03 0000ffffffff8010 00000000ffffac03 
00000000ffffffff 000000000000
0000 ffffffff8010002c ffffffff8010d0ca
(XEN)
(XEN)    0000000000000000 ffffffff802f6d00 0000000000000000 00000000ffffffff 
0000000000000001 000000000000
0246 0000010000000000 0000000000000008
(XEN)    ffffffff8010d0ca
(XEN)    00000000ffffac47 000000000000e033 00000000ffffac47 0000000000000246 
0000000000000000 ffff88000002
7f28 ffffffff8010d0ca
(XEN)    000000000000e02b
(XEN)    0000000000000000 0000000000000000 0000000000000000 0000000000000000 
0000000000000001 000000000000
0000 0000010000000000
(XEN)
(XEN)    Xen call trace:
(XEN)    ffffffff8010d0ca [<ffff83000011e108>]000000000000e033  
desched_extra_dom+0x1c3/0x38a
(XEN)    0000000000000246 [<ffff83000011e6c3>]ffffffff803adf68  
sedf_do_schedule+0x123/0x3c6
(XEN)
(XEN)    000000000000e02b [<ffff8300001217ae>]0000000000000000  
__enter_scheduler+0x106/0x39b
(XEN)    0000000000000000 [<ffff8300001212e5>]0000000000000000  
do_block+0xb4/0xbb
(XEN)
(XEN) [<ffff8300001213a2>]Xen call trace:
(XEN)     do_sched_op+0x4d/0xcf
(XEN)    [<ffff830000159260>][<ffff83000011e108>] syscall_enter+0xa0/0xfa
(XEN)     desched_extra_dom+0x1c3/0x38a
(XEN)
(XEN) [<ffff83000011e6c3>]************************************
(XEN)  sedf_do_schedule+0x123/0x3c6
(XEN)    CPU0 FATAL TRAP 0 (divide error), ERROR_CODE 0000, IN INTERRUPT 
CONTEXT.
(XEN) [<ffff8300001217ae>]System shutting down -- need manual reset.
(XEN) ************************************
(XEN)  __enter_scheduler+0x106/0x39b


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