Re: Question about Xen reboot on panic

[Wei Liu <wei.liu2@citrix.com>]

On Thu, Nov 12, 2015 at 12:52:56PM +0000, Andrew Cooper wrote:
> On 12/11/15 02:10, Meng Xu wrote:
> > Hi Andrew,
> >
> > 2015-11-11 18:34 GMT-05:00 Andrew Cooper <andrew.cooper3@citrix.com>:
> >> On 11/11/2015 23:21, Meng Xu wrote:
> >>>> Finally, I can't tell from your paste below, but ensure that you are
> >>>> always using a debug hypervisor.
> >>> The source file Config.mk under the xen folder has
> >>> debug ?= y
> >>>
> >>> In addition,  "xl dmesg |grep debug" gives me:
> >>>
> >>> (XEN) Xen version 4.6-unstable (root@) (gcc (Ubuntu/Linaro
> >>> 4.6.3-1ubuntu5) 4.6.3) debug=y Wed Nov 11 17:06:30 EST 2015
> >>>
> >>> So I guess I'm using the debug hypervisor.
> >> You are
> >>
> >>> I reboot the system after removing all of those useless options (that
> >>> is, no more "reboot=k panic=2 panic_on_oops=1" in the Xen boot command
> >>> line.)
> >>>
> >>> Is there anything else I can do to force Xen always reboot at panic or oops?
> >> Unless you specify noreboot, Xen will try its hardest to reboot the
> >> system.  It is possible that you have a dodgy firmware which interacts
> >> poorly with the default methods.
> >>
> >> Does normal reboot from dom0 work as intended?
> > Yes. Before Xen crashes, I can reboot the machine dom0 or from a serial port.
> >
> >> If not, debug in the following order:
> >>
> >> * `reboot` from the dom0 shell
> >> * `echo b > /proc/sysrq-trigger` from the dom0 shell
> >> * `xl debug-keys R` from the dom0 shell
> > All of these three approaches can reboot the machine successfully.
> >
> >
> >> * CTRL-A x3, R from the serial console
> > I think "Ctrl-A" means that I should press "Ctrl + A" three times. Am I correct?
> > When I press Ctrl-A twice, it shows "No other window"; after I press
> > "Ctrl-A" for three consecutive times, and press R (or r), it shows
> > "+wrap" in the serial port.
> 
> In which case the program you are using locally to connect to the serial
> console (Minicom / screen/ putty?) is intercepting CTRL-a for its own
> purposes.
> 
> In screen for example, you need to send CTRL-a a to send a "CTRL-a" on
> the serial.
> 

And for minicom it is "Ctrl-a Ctrl-a" to send "Ctrl-a".