DragonFlyBSD

I have noticed that the coredump only occurs if I interrupt the process
(by Ctrl+C):

• /dev/ad2s1a
• Last Mounted on /mnt/test
• Phase 1 - Check Blocks and Sizes
• Phase 2 - Check Pathnames
• Phase 3 - Check Connectivity
• Phase 4 - Check Reference Counts
• Phase 5 - Check Cyl groups
  3076 files, 56890 used, 136613 free (61 frags, 17069 blocks, 0.0%
  fragmentation)
  ad2: TIMEOUT - WRITE_DMA retrying (1 retry left) LBA=79
  ^Cad2: TIMEOUT - WRITE_DMA retrying (0 retries left) LBA=79
  ad2: FAILURE - WRITE_DMA timed out LBA=79
  fsck in free(): error: free_pages: pointer to wrong pageAbort (core dumped)
  virtualdragon# Aug 11 16:45:30 virtualdragon kernel: pid 995 (fsck), uid
  0: exit
  ed on signal 6 (core dumped)

Now I include a backtrace:

(gdb) bt
#0 0x080773ac in kill ()
#1 0x0807509e in abort ()
#2 0x0805e611 in ?? ()
#3 0x0805e63b in ?? ()
#4 0x0805ef75 in ?? ()
#5 0x0805f7ca in free ()
#6 0x08053ba3 in ckfini (markclean=0) at utilities.c:266
#7 0x08054701 in catch (sig=2) at utilities.c:487
#8 <signal handler called>
#9 0x08055e9c in write ()
#10 0x08054009 in bwrite (fd=4, buf=0x28085000 "", blk=16, size=8192) at
utilities.c:350
#11 0x08053996 in flush (fd=4, bp=0x808baa0) at utilities.c:226
#12 0x08053c80 in ckfini (markclean=1) at utilities.c:281
#13 0x0804c3b3 in checkfilesys (filesys=0xbfbff9b9 "/dev/ad2s1a",
mntpt=0x0, auxdata=0, child=0) at main.c:339
#14 0x0804bc1d in main (argc=0, argv=0xbfbff8d4) at main.c:148

Hope this helps a bit more.

Regards,
Antonio Huete

There must be some kind of permission issue, because this problem goes away by
running QEMU-KVM as root

This can be closed.

What's the cause/solution?

cheers
simon

The problem was on the host (Linux) and not in the guest (DF). It seems that
although running QEMU-KVM with a user in kvm group, there are some problems
accessing the disk images (or something else). This is solved by running
QEMU-KVM as root.