On Wed, Jul 13, 2022 at 03:10:37PM +0200, Laszlo Ersek wrote:
On 07/13/22 13:27, Richard W.M. Jones wrote:
>
> It's not 100% reproducible, but it seems to happen reasonably often.
> Unfortunately it only happens on ppc64le (so far). The error message
> lacks sufficient detail to tell what's going on.
>
> nbdkit: backend.c:624: backend_pread: Assertion `backend_valid_range (c, offset,
count)' failed.
> nbdkit: backend.c:624: backend_pread: Assertion `backend_valid_range (c, offset,
count)' failed.
>
> Full log attached.
"tests/disk" has size 105923072.
Considering all the count=... offset=... lines in the last section of
the log, there isn't one line where backend_valid_range():
return count > 0 && offset <= c->exportsize &&
offset + count <= c->exportsize;
would return false.
I've printed a table, with offset, count, and offset+count colums, from
the log entries, then sorted the table three times separately, each time
by a different column. I got the following min and max elements:
offset count offset+count
--------- --------- -----------
0 105923072 105923072 (min by offset)
105906176 16896 105923072 (max by offset)
0 4096 4096 (min by count)
0 105923072 105923072 (max by count)
0 4096 4096 (min by end)
105906176 16896 105923072 (max by end)
All of these look valid... I think you'll have to look at the coredump
with gdb.
Indeed - unfortunately the coredump is on a Fedora build system :-(
I'll reserve a POWER machine later (unless someone gets there first).
Rich.
--
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