Re: [PATCH v2 01/16] migration: vmstate_save_state_v: fix double error_setg

[Fabiano Rosas <farosas@suse.de>]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:

> We may call error_setg twice on same errp if inner
> vmstate_save_state_v() or vmstate_save_state() call fails. Next we will
> crash on assertion in error_setv().
>
> Fixes: 848a0503422d043 "migration: Update error description outside migration.c"
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>  migration/vmstate.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/migration/vmstate.c b/migration/vmstate.c
> index 4d28364f7b..fccd030dfd 100644
> --- a/migration/vmstate.c
> +++ b/migration/vmstate.c
> @@ -539,6 +539,9 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
>                  } else {
>                      ret = inner_field->info->put(f, curr_elem, size,
>                                                   inner_field, vmdesc_loop);
> +                    if (ret < 0) {
> +                        error_setg(errp, "put failed");
> +                    }
>                  }
>  
>                  written_bytes = qemu_file_transferred(f) - old_offset;
> @@ -551,8 +554,8 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
>                  }
>  
>                  if (ret) {
> -                    error_setg(errp, "Save of field %s/%s failed",
> -                                vmsd->name, field->name);
> +                    error_prepend(errp, "Save of field %s/%s failed: ",
> +                                  vmsd->name, field->name);
>                      if (vmsd->post_save) {
>                          vmsd->post_save(opaque);
>                      }

Reviewed-by: Fabiano Rosas <farosas@suse.de>