Re: Qemu (Re: NiLFS support on Pinebook)

[Reinoud Zandijk <reinoud-qavaossjCcEdnm+yROfE0A@public.gmane.org>]

Hi Ryusuke,

On Fri, Feb 28, 2020 at 11:55:03AM +0100, Reinoud Zandijk wrote:
> Can you recommend a lightweigth linux distro with nilfs support that runs fast
> in `unaided' Qemu?  I.e. with only the `tcg' acceleration and with no
> graphics?

I've settled for a Debian without graphics and it works quite well AND it has
NiLFS2 support!

Testing it on one of my older test NiLFS2 images I had around it paniced when
I did this:

qemu-system-x86_64 -drive file=root.debian.fs,format=raw -accel
  tcg,thread=multi -smp cpus=4 -m 4096 -drive
  file=/usr/tmp/nilfs.4g.img,format=raw
....
    mount.nilfs2 /dev/sdb1 /mnt
    touch /mnt/UDF
wait a second or two
    CRASH

Note that /mnt/UDF exists and is a directory. It gives a NULL pointer
dereference at 0xa8
Call trace:
    __test_set_page_writeback+0x38c/0x3f0
    nilfs_segctor_do_construct+0x190f
    nilfs_segctor_construct+0x1f5
    nilfs_segctor_thread+0x127
....
RIP: 0010:percpu_counter_add_batch+0x04
....

Do you like to receive a copy of this image? It used to work fine and should
only be touched by your NiLFS code.

With regards,
Reinoud