[Libguestfs] Virt-v2v conversion issue

VONDRA Alain AVONDRA at unicef.fr
Wed Oct 15 12:23:17 UTC 2014

Now, the conversion hangs on the first disk at 54,03/100%, here is the gdb result :

(gdb) t a a bt

Thread 2 (Thread 0x7f0f3cea9700 (LWP 9583)):
#0  sem_timedwait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S:101
#1  0x00007f0f45b765e7 in qemu_sem_timedwait ()
#2  0x00007f0f45b0750c in worker_thread ()
#3  0x00007f0f4203bdf3 in start_thread (arg=0x7f0f3cea9700) at pthread_create.c:308
#4  0x00007f0f41d6901d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

Thread 1 (Thread 0x7f0f45aa88c0 (LWP 9582)):
#0  0x00007f0f41d5eb0f in __GI_ppoll (fds=0x7f0f470d7a00, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:56
#1  0x00007f0f45b146db in qemu_poll_ns ()
#2  0x00007f0f45b15430 in aio_poll ()
#3  0x00007f0f45b0eedd in bdrv_prwv_co ()
#4  0x00007f0f45b0efd3 in bdrv_rw_co ()
#5  0x00007f0f45b05b35 in img_convert ()
#6  0x00007f0f41c94af5 in __libc_start_main (main=0x7f0f45b01e80 <main>, argc=10, ubp_av=0x7fff19cb3ab8, init=<optimized out>, fini=<optimized out>,
    rtld_fini=<optimized out>, stack_end=0x7fff19cb3aa8) at libc-start.c:274
#7  0x00007f0f45b022ed in _start ()


-----Message d'origine-----
De : Richard W.M. Jones [mailto:rjones at redhat.com] 
Envoyé : mardi 14 octobre 2014 22:52
À : VONDRA Alain
Cc : libguestfs at redhat.com
Objet : Re: [Libguestfs] Virt-v2v conversion issue

On Tue, Oct 14, 2014 at 03:40:22PM +0000, VONDRA Alain wrote:
> Rich,
> I've followed your instructions to trace, but I am not very skilful with gdb, maybe I made a mistake :
> (1) As root do:
>   echo core.%p > /proc/sys/kernel/core_pattern  -> OK
> (2) Before running virt-v2v, do:
>   ulimited -c unlimited                 -> I think it's ulimit -c unlimited     -> -> OK
> and you should get a core.* file in the current directory when qemu-img segfaults.  Attach that file to gdb to get a stack trace:
>   gdb /usr/bin/qemu-img core.XYZ                -> Do I need to wait the crash becase I don't have any core ???

Yes, you have to wait for qemu-img to crash before there will be a core dump.  If it's not crashing, then connect to qemu-img directly, something like this:

  gdb /usr/bin/qemu-img `pidof qemu-img`

and run this command:

>   (gdb) t a a bt

to show the stack trace in all threads.

If qemu-img is consuming CPU then it's probably not hung.

I'm still interested to find out why fstrim didn't work.  Can you run:

guestfish --ro -d unc-srv-qual03
><fs> run
><fs> part-list /dev/sda
><fs> part-list /dev/sdb
><fs> part-list /dev/sdc
><fs> part-list /dev/sdd

I'd be interested to see if the partitions are unaligned, which is the only reason why fstrim should fail on NTFS.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-builder quickly builds VMs from scratch http://libguestfs.org/virt-builder.1.html

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