Re: [Qemu-devel] [Bug 1684239] [NEW] vvfat core dump when enabling RW

[Hervé Poussineau]

Hi Rolando,

Le 19/04/2017 à 19:45, Rolando Zappacosta a écrit :
> Public bug reported:
>
> Hi guys,
>
> I'm getting this qemu crash message:
> > > > qemu-system-x86_64: /build/qemu-TziMIO/qemu-2.5+dfsg/block/vvfat.c:2290: commit_direntries: 
> > > > Assertion `!strncmp(s->directory.pointer, "QEMU", 4)' failed.
> > > > Aborted (core dumped)
> when launching qemu with this options for a VVFAT drive:
> > > > -drive file=fat:rw:./ROOT,if=virtio
> (same happens when using cache=none and/or if=ide)
>
> "uname -a" system info is:
> > > > Linux RJZ-WRK-LNX 4.4.0-72-generic #93-Ubuntu SMP Fri Mar 31 14:07:41 UTC 2017 
> > > > x86_64 x86_64 x86_64 GNU/Linux
> and "qemu --version" is:
> > > > QEMU emulator version 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.10), Copyright (c) 
> > > > 2003-2008 Fabrice Bellard
>
> Not sure what logs to attach but I'll be glad to upload whatever needed.
>
> Thanks in advance for you help,
> Rolando

This bug has been fixed in following commit:

commit ebb72c9f066e5f85259e1541a6d3fb5bfd6e73ff
Author: Kevin Wolf <address@hidden>
Date:   Wed Apr 27 14:11:38 2016 +0200

    vvfat: Fix volume name assertion

    Commit d5941dd made the volume name configurable, but it didn't consider
    that the rw code compares the volume name string to assert that the
    first directory entry is the volume name. This made vvfat crash in rw
    mode.

    This fixes the assertion to compare with the configured volume name
    instead of a literal string.

    Cc: address@hidden
    Signed-off-by: Kevin Wolf <address@hidden>
    Reviewed-by: Markus Armbruster <address@hidden>
    Reviewed-by: Stefan Hajnoczi <address@hidden>

The fix is present since v2.6.0
As you're using v2.5.0, can you try with a newer QEMU version?

Regards,

Hervé