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

[Guillaume Thouvenin <guillaume.thouvenin@xxxxxxxx>]

I tested the changset 8627 and the fatal trap is a little bit different
because new messages (produced by the linux-2.6.12.6-xenU from domain 1
or by Xen???) are caught on the serial link. The test is the same, I
start one unprivileged domain and run two commands that are:     

# xm sched-sedf 1 20000000 5000000 0 0 0
# xm sched-sedf 1 20000000 0 0 1 0

Here is the Xen message:

(XEN) CPU:    3
(XEN) RIP:    e010:[<ffff8300001101f2>] desched_extra_dom+0xc2/0x190
(XEN) RFLAGS: 0000000000010006   CONTEXT: hypervisor
(XEN) rax: 00000004c4b40000   rbx: ffff830000ff8f00   rcx: ffff830000ff8f30
(XEN) rdx: 0000000000000000   rsi: 0000000000020000   rdi: 00000065ac412840
(XEN) rbp: 00000065ac412840   rsp: ffff8300001dbe20   r8:  ffff8300001eec80
(XEN) r9:  ffff830000fce080   r10: 0000000000000001   r11: 0000000000000001
(XEN) r12: ffff830000ff8f10   r13: 0000000000000003   r14: 0000000000000003Timer
 ISR/0: Time went backwards: delta=-40045272 cpu_delta=49954728 shadow=437002448
223 off=87566263 processed=437130059504 cpu_processed=437040059504
(XEN)  0: 437040059504
r15: ffff830000180f80   cr0: 000000008005003b   cr3: 0000000104c3a000 1: 4370900
64536

 2: 437130064536
(XEN)  3: 436660064536
Xen stack trace from rsp=ffff8300001dbe20:Timer ISR/0: Time went backwards: delt
a=-235630433 cpu_delta=234369567 shadow=437002448223 off=311980971 processed=437
550059504
 cpu_processed=437080059504
(XEN)  0: 437080059504
    1: 437550064536
ffff83000010f7b6  2: 437550064536
ffff8300001dc080  3: 436660064536
ffff8300001dc080 Timer ISR/0: Time went backwards: delta=-369042259 cpu_delta=19
0957741 shadow=437002448223 off=498569094 processed=437870059504ffff83000011a3f3
  cpu_processed=437310059504

 0: 437310059504
(XEN)  1: 437870064536
    2: 437870064536
0000000000000000  3: 436660064536
ffff830000ff8f20 Timer ISR/0: Time went backwards: delta=-507439348 cpu_delta=17
2560652 shadow=437002448223 off=670172008 processed=438180059504ffff830000ff8f30
  cpu_processed=437500059504
ffff830000180fa0  0: 437500059504

 1: 438170064536
(XEN)  2: 438170064536
    3: 436660064536
0000000000000003 Timer ISR/0: Time went backwards: delta=-635830026 cpu_delta=17
4169974 shadow=437002448223 off=841781333 processed=43848005950400000065ac412840
  cpu_processed=437670059504
0000000000000180  0: 437670059504
ffff830000fce080  1: 438480064536

 2: 438480064536
(XEN)  3: 436660064536
   Timer ISR/0: Time went backwards: delta=-765939247 cpu_delta=184060753 shadow
=437002448223 off=1021672118 processed=43879005950ffff830000110d98 4 cpu_process
ed=437840059504
000000000007a120  0: 437840059504
ffff830000180e00  1: 438790064536
000000000007a120  2: 438790064536

 3: 436660064536
(XEN) Timer ISR/0: Time went backwards: delta=-907230826 cpu_delta=182769174 sha
dow=437002448223 off=1200380532 processed=43911005950   4 cpu_processed=43802005
9504
ffff830000174ba0  0: 438020059504
0000000000000000  1: 439110064536
0000000000000003  2: 439110064536
ffff830000fce0a0  3: 436660064536

Timer ISR/0: Time went backwards: delta=-726155685 cpu_delta=183844315 shadow=43
7002448223 off=1381455632 processed=43911005950(XEN) 4 cpu_processed=43820005950
4
    0: 438200059504
0000000000000000  1: 439110064536
0000000000000000  2: 439110064536
ffffffff8010002c  3: 436660064536
00000000ffffffff Timer ISR/0: Time went backwards: delta=-1173955180 cpu_delta=1
76044820 shadow=437002448223 off=1553656202 processed=4397300595
04 cpu_processed=438380059504
(XEN)  0: 438380059504
    1: 439730064536
0000ffffffff8010  2: 439730064536
ffffffff803affb0  3: 436660064536
ffff8300001109f5 Timer ISR/0: Time went backwards: delta=-1301160567 cpu_delta=1
78839433 shadow=437002448223 off=1726450802 processed=440030059500000000ffffffff
 04 cpu_processed=438550059504

 0: 438550059504
(XEN)  1: 440030064536
    2: 440030064536
ffff830000110a7b  3: 436660064536
ffffffff803affb0 ffff830000fce080 ffffffff802f7500
(XEN)    ffff8300001384ac ffffffff803affb0 0000ffffffff8010 00000000ffffffff
(XEN)    ffffffff8010002c ffffffff802f7500 00000000ffffffff 0000000000000246
(XEN)    0000000000000001 00000000ffffb1bd 0000000000000310 0000000000000000
(XEN)    ffffffff8010fc5f 0000000000000000 0000000000000000 0000000000000001
(XEN)    0000010000000000 ffffffff8010fc5f 000000000000e033 0000000000000246
(XEN)    ffffffff803aff80 000000000000e02b 0000000000000000 0000000000000000
(XEN)    0000000000000000 0000000000000000 0000000000000003 ffff830000fce080
(XEN) Xen call trace:
(XEN)    [<ffff8300001101f2>] desched_extra_dom+0xc2/0x190
(XEN)    [<ffff83000010f7b6>] sedf_do_schedule+0xc6/0x200
(XEN)    [<ffff83000011a3f3>] context_switch+0x173/0x1a0
(XEN)    [<ffff830000110d98>] __enter_scheduler+0x78/0x250
(XEN)    [<ffff8300001109f5>] do_block+0x85/0x90
(XEN)    [<ffff830000110a7b>] do_sched_op+0x7b/0x110
(XEN)    [<ffff8300001384ac>] syscall_enter+0x5c/0x61
(XEN)
(XEN) ************************************
(XEN) CPU3 FATAL TRAP 0 (divide error), ERROR_CODE 0000, IN INTERRUPT CONTEXT.
(XEN) System shutting down -- need manual reset.
(XEN) ************************************
printk: 3 messages suppressed.
Timer ISR/0: Time went backwards: delta=-2202039443 cpu_delta=927960557 shadow=4
37002448223 off=2944602314 processed=442130059504 cpu_processed=439000059504
 0: 439000059504
 1: 442120064536
 2: 442120064536
 3: 436660064536

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