[PATCH QEMU HCI-8.1 v2 10/24] migration: vmstate_save_state_v: fix double error_setg

[Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>]

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

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().

andrey.drobyshev:
    This commit is cherry-picked as-is, with no modifications, from the
    upstream commit d41ce10d0f5a.

Fixes: 848a0503422d043 "migration: Update error description outside migration.c"
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20260304212303.667141-2-vsementsov@yandex-team.ru
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/vmstate.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/migration/vmstate.c b/migration/vmstate.c
index aea41c09946..04903131257 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -523,6 +523,9 @@ 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;
@@ -535,8 +538,8 @@ 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);
                     }

-- 
2.47.1