From 1b38f5208faaddd0c9ec17c3bee80ab87afa007a Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 14 Feb 2018 19:22:46 -0500 Subject: [PATCH] qom: Fix invalid error check in property_get_str() When a function returns a null pointer on error and only on error, you can do if (!foo(foos, errp)) { ... handle error ... } instead of the more cumbersome Error *err = NULL; if (!foo(foos, &err)) { error_propagate(errp, err); ... handle error ... } A StringProperty's getter, however, may return null on success! We then fail to call visit_type_str(). Screwed up in 6a146eb, v1.1. Fails tests/qom-test in my current, heavily hacked QAPI branch. No reproducer for master known (but I didn't look hard). Backports commit a479b21c111a87a50203a7413c4e5ec419fc88dd from qemu --- qemu/qom/object.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/qemu/qom/object.c b/qemu/qom/object.c index da3dfcca..c2ce5213 100644 --- a/qemu/qom/object.c +++ b/qemu/qom/object.c @@ -1359,12 +1359,16 @@ static void property_get_str(struct uc_struct *uc, Object *obj, Visitor *v, void { StringProperty *prop = opaque; char *value; + Error *err = NULL; - value = prop->get(uc, obj, errp); - if (value) { - visit_type_str(v, &value, name, errp); - g_free(value); + value = prop->get(uc, obj, &err); + if (err) { + error_propagate(errp, err); + return; } + + visit_type_str(v, &value, name, errp); + g_free(value); } static int property_set_str(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,