Re: [Qemu-devel] [PATCH] savevm: fix corruption in vmstate_subsection_load().

[Yoshiaki Tamura]

2010/12/14 Yoshiaki Tamura <address@hidden>:
> Although it's rare to happen in live migration, when the head of a
> byte stream contains 0x05 which is the marker of subsection, the
> loader gets corrupted because vmstate_subsection_load() continues even
> the device doesn't require it.  This patch adds a checker whether
> subsection is needed, and skips following routines if not needed.
>
> Signed-off-by: Yoshiaki Tamura <address@hidden>
> ---
>  savevm.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/savevm.c b/savevm.c
> index d38f79e..72f6249 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1633,6 +1633,12 @@ static const VMStateDescription 
> *vmstate_get_subsection(const VMStateSubsection
>  static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription 
> *vmsd,
>                                    void *opaque)
>  {
> +    const VMStateSubsection *sub = vmsd->subsections;
> +
> +    if (!sub || !sub->needed) {
> +        return 0;
> +    }
> +
>     while (qemu_peek_byte(f) == QEMU_VM_SUBSECTION) {
>         char idstr[256];
>         int ret;
> @@ -1645,7 +1651,7 @@ static int vmstate_subsection_load(QEMUFile *f, const 
> VMStateDescription *vmsd,
>         idstr[len] = 0;
>         version_id = qemu_get_be32(f);
>
> -        sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr);
> +        sub_vmsd = vmstate_get_subsection(sub, idstr);
>         if (sub_vmsd == NULL) {
>             return -ENOENT;
>         }
> --
> 1.7.1.2
>
>
>

Hi Juan,

This is an error that always happen with Kemari.  Could you tell
me if I'm fixing incorrectly?

Thanks,

Yoshi