Hi
On Tue, Feb 2, 2021 at 5:02 PM Priyankar Jain <priyankar.j...@nutanix.com>
wrote:
> This commit fixes an issue where migration is failing in the load phase
> because of a false alarm about data unavailability.
>
> Following is the error received when the amount of data to be transferred
> exceeds the default buffer size setup by G_BUFFERED_INPUT_STREAM(4KiB),
> even when the maximum data size supported by this backend is 1MiB
> (DBUS_VMSTATE_SIZE_LIMIT):
>
> dbus_vmstate_post_load: Invalid vmstate size: 4364
> qemu-kvm: error while loading state for instance 0x0 of device
> 'dbus-vmstate/dbus-vmstate'
>
> This commit sets the size of the input stream buffer used during load to
> DBUS_VMSTATE_SIZE_LIMIT which is the maximum amount of data a helper can
> send during save phase.
> Secondly, this commit makes sure that the input stream buffer is loaded
> before
> checking the size of the data available in it, rectifying the false alarm
> about
> data unavailability.
>
> Signed-off-by: Priyankar Jain <priyankar.j...@nutanix.com>
>
Fixes: 5010cec2bc87 ("Add dbus-vmstate object")
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
> backends/dbus-vmstate.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/backends/dbus-vmstate.c b/backends/dbus-vmstate.c
> index bd050e8..3b8a116 100644
> --- a/backends/dbus-vmstate.c
> +++ b/backends/dbus-vmstate.c
> @@ -204,6 +204,8 @@ static int dbus_vmstate_post_load(void *opaque, int
> version_id)
> m = g_memory_input_stream_new_from_data(self->data, self->data_size,
> NULL);
> s = g_data_input_stream_new(m);
> g_data_input_stream_set_byte_order(s,
> G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
> + g_buffered_input_stream_set_buffer_size(G_BUFFERED_INPUT_STREAM(s),
> + DBUS_VMSTATE_SIZE_LIMIT);
>
> nelem = g_data_input_stream_read_uint32(s, NULL, &err);
> if (err) {
> @@ -241,11 +243,23 @@ static int dbus_vmstate_post_load(void *opaque, int
> version_id)
> }
>
> len = g_data_input_stream_read_uint32(s, NULL, &err);
> + if (len > DBUS_VMSTATE_SIZE_LIMIT) {
> + error_report("%s: Invalid vmstate size: %u", __func__, len);
> + return -1;
> + }
> +
> + g_buffered_input_stream_fill(G_BUFFERED_INPUT_STREAM(s), len,
> NULL,
> + &err);
> + if (err) {
> + goto error;
> + }
> +
> avail = g_buffered_input_stream_get_available(
> G_BUFFERED_INPUT_STREAM(s));
> -
> - if (len > DBUS_VMSTATE_SIZE_LIMIT || len > avail) {
> - error_report("%s: Invalid vmstate size: %u", __func__, len);
> + if (len > avail) {
> + error_report("%s: Not enough data available to load for Id:
> '%s'. "
> + "Available data size: %lu, Actual vmstate size: %u",
> + __func__, id, avail, len);
> return -1;
> }
>
> --
> 1.8.3.1
>
>
