Re: [Xen-devel] [PATCH v5 00/21] libxl: domain save/restore: run in a separate process

[Shriram Rajagopalan <rshriram@xxxxxxxxx>]

Ian,

 The code segfaults. Here are the system details and error traces from gdb.

 

My setup:

dom0 : ubuntu 64bit, 2.6.32-39 (pvops kernel), 

           running latest xen-4.2-unstable (built from your repo)

           tools stack also built from your repo (which I hope has all the latest patches).

domU: ubuntu 32bit PV, xenolinux kernel (2.6.32.2 - novel suse version) 

           with suspend event channel support

As a sanity check, I tested xl remus with latest tip from xen-unstable 

mercurial repo, c/s: 25496:e08cf97e76f0

Blackhole replication (to /dev/null) and localhost replication worked as expected

and the guest recovered properly without any issues.

These are the commands, just in case you wish to try them yourself on any guest.

 nohup xl remus -b -i 100 domU dummy >logfile 2>&1 &

 nohup xl remus -i 100 -e domU localhost >logfile 2>&1 &

With the your repo, both blackhole replication and localhost replication segfault. 

I havent tested remote replication. [I dont know if the segfault is from your patches

or someone else's :) ]

The source domain is left in ---ss- state. 

With localhost replication, the targetdomain--incoming becomes operational,

but without renaming.

Blackhole replication:

================

xl error: 

----------

xc: error: Could not get domain info (3 = No such process): Internal error

libxl: error: libxl.c:388:libxl_domain_resume: xc_domain_resume failed for domain 4154075147: No such process

libxl: error: libxl_dom.c:1184:libxl__domain_save_device_model: unable to open qemu save file ?8b: No such file or directory

I also ran xl in GDB to get a stack trace and hopefully some useful debug info.

gdb traces: http://pastebin.com/7zFwFjW4

Localhost replication: Partial success, but xl still segfaults

 dmesg shows

 [ 1399.254849] xl[4716]: segfault at 0 ip 00007f979483a417 sp 00007fffe06043e0 error 6 in libxenlight.so.2.0.0[7f9794807000+4d000]

xl error: 

migration target: Ready to receive domain.

Saving to migration stream new xl format (info 0x0/0x0/487)

Loading new save file <incoming migration stream> (new xl fmt info 0x0/0x0/487)

 Savefile contains xl domain config

xc: error: Could not get domain info (3 = No such process): Internal error

libxl: error: libxl.c:388:libxl_domain_resume: xc_domain_resume failed for domain 2491594763: No such process

libxl: error: libxl_dom.c:1184:libxl__domain_save_device_model: unable to open qemu save file `??: No such file or directory

xc: error: 0-length read: Internal error

xc: error: read_exact_timed failed (read rc: 0, errno: 0): Internal error

xc: error: Error when reading batch size (0 = Success): Internal error

xc: error: error when buffering batch, finishing (0 = Success): Internal error

migration target: Remus Failover for domain 3

libxl: error: libxl.c:313:libxl__domain_rename: domain with name "drbd-vm" already exists.

migration target (Remus): Failed to rename domain from drbd-vm--incoming to drbd-vm:-6

I see calls related to qemu, but I am running a PV guest!

thanks

shriram

On Tue, Jun 26, 2012 at 2:44 PM, Shriram Rajagopalan <rshriram@xxxxxxxxx> wrote:

Shriram, would you care to take a look at this series and perhaps
retest it ?

Sure will do.

If you would prefer a git branch to a series of patches, you can find
it here:
 http://xenbits.xen.org/gitweb/?p=people/iwj/xen-unstable.git;a=shortlog;h=refs/heads/for-shriram
 git://xenbits.xen.org/people/iwj/xen-unstable.git#shriram
NB that branch is REBASING.

I am not too familiar with the git lingo.. What did you mean by "branch is rebasing" ?

Am I supposed to do something special, apart from the normal process below: 

git clone git://xen....

git checkout -b for-shriram origin/for-shriram 

thanks

shriram

 

Thanks,
Ian.

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