Re: [Crash-utility] Xen Dumping - Expectations
Joshua Giles wrote:
Not quite sure if this or the kdump list is appropriate for this
discussion, but I will start here...
Why kdump?
I've been playing with xen dumping on x86_64 and x86 (RHEL5 20061006.2);
The following is a simple crash session on x86_64 (using "xm dump-core
-L"):
Interesting. It kind of looks like there's something different about the
corefile contents when using "xm dump-core" as opposed to forcing
a "real" crash, i.e., such as when using sysrq-c?
`crash /usr/lib/debug/lib/modules/2.6.18-1.2714.el5xen/vmlinux /xen/dump/Live_Dump`
"WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
WARNING: possibly bogus exception frame
KERNEL: /usr/lib/debug/lib/modules/2.6.18-1.2714.el5xen/vmlinux
DUMPFILE: /xen/dump/Live_Dump
CPUS: 1
DATE: Mon Oct 16 11:46:02 2006
UPTIME: 00:07:12
LOAD AVERAGE: 0.00, 0.02, 0.00
TASKS: 67
NODENAME: dhcp78-103.lab.boston.redhat.com
RELEASE: 2.6.18-1.2714.el5xen
VERSION: #1 SMP Mon Oct 2 17:26:27 EDT 2006
MACHINE: x86_64 (3200 Mhz)
MEMORY: 264 MB
PANIC: ""
PID: 0
COMMAND: "swapper"
TASK: ffffffff804c5ae0 [THREAD_INFO: ffffffff805de000]
CPU: 0
STATE: TASK_RUNNING (ACTIVE)
WARNING: panic task not found
crash>crash> bt
crash>
crash> ffffff805dff68] raw_safe_halt at ffffffff8026c989
crash> ffffff805dff88] xen_idle at ffffffff8026a04d
crash> ffffff805dff98] cpu_idle at ffffffff80248e4d"
*WARNINGS, WARNINGS, WARNINGS (no such problem like this for i386.)
*The output of bt doesn't actually work as expected. You have to hit
carriage return a couple times before you see anything.
#####i386#############################################################
crash /usr/lib/debug/lib/modules/2.6.18-1.2714.el5xen/vmlinux /xen/dump/live_dump
This GDB was configured as "i686-pc-linux-gnu"...
KERNEL: /usr/lib/debug/lib/modules/2.6.18-1.2714.el5xen/vmlinux
DUMPFILE: /xen/dump/live_dump
CPUS: 1
DATE: Mon Oct 16 11:47:28 2006
UPTIME: 00:08:30
LOAD AVERAGE: 0.00, 0.04, 0.03
TASKS: 68
NODENAME: dhcp78-115.lab.boston.redhat.com
RELEASE: 2.6.18-1.2714.el5xen
VERSION: #1 SMP Mon Oct 2 17:40:51 EDT 2006
MACHINE: i686 (3200 Mhz)
MEMORY: 264 MB
PANIC: ""
PID: 0
COMMAND: "swapper"
TASK: c0674a60 [THREAD_INFO: c07a3000]
CPU: 0
STATE: TASK_RUNNING (ACTIVE)
WARNING: panic task not found
crash> bt
crash>
crash> 7a3fa8] hypercall_page at c04013a7
crash> 7a3fb8] xen_idle at c0402bdb
crash> 7a3fc0] cpu_idle at c0402d02
crash>
*The output of bt doesn't actually work as expected. You have to hit
carriage return a couple times before you see anything and the addresses
are partially visible...
*panic task not found?
Are these known problems with crash and/or xen?
No -- but it's never been tested with this new "xm dump-core" facility.
Is xen dumping
supported on x86, x86_64, ppc, ia64?
x86 and x86_64 only -- ia64 is still TBD.
Can anyone point me to docs that
talk about xen dumping (e.g. internal/external wiki?)
None that I'm aware of...
The best thing that you can do is come over to my office,
and we'll get to the bottom of this. In the meantime, it would
be interesting to know whether the behavior above is the
same when you:
1. log into the domU
2. echo c > /proc/sysrq-trigger
Anyway, when you get the time, please stop by.
Thanks,
Dave