On Wed, 13 Feb 2019 14:30:55 +0100 Markus Armbruster <[email protected]> wrote:
> Igor Mammedov <[email protected]> writes: > > > QEMU will crashes with > > qapi/qobject-output-visitor.c:210: qobject_output_complete: Assertion > > `qov->root && ((&qov->stack)->slh_first == ((void *)0))' failed > > when trying to get value of empty hostmem.host-nodes property. > > > > Fix it by calling visitor even if host-nodes wasn't set > > before exiting from property getter to return empty list. > > host-nodes or host_nodes? > > If local variable host_nodes: that one's always set. The case you fix > has it set to NULL. it's about property host-nodes: value = find_first_bit(backend->host_nodes, MAX_NODES); if (value == MAX_NODES) { goto ret; } when no bits set, it exits without visiting being returned list. I'll send v2 with commit message giving more explanation to make it clearer. > > Signed-off-by: Igor Mammedov <[email protected]> > > --- > > backends/hostmem.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/backends/hostmem.c b/backends/hostmem.c > > index 0c8ef17..fe14be5 100644 > > --- a/backends/hostmem.c > > +++ b/backends/hostmem.c > > @@ -86,7 +86,7 @@ host_memory_backend_get_host_nodes(Object *obj, Visitor > > *v, const char *name, > > > > value = find_first_bit(backend->host_nodes, MAX_NODES); > > if (value == MAX_NODES) { > > - return; > > + goto ret; > > } > > > > *node = g_malloc0(sizeof(**node)); > > @@ -104,6 +104,7 @@ host_memory_backend_get_host_nodes(Object *obj, Visitor > > *v, const char *name, > > node = &(*node)->next; > > } while (true); > > > > +ret: > > visit_type_uint16List(v, name, &host_nodes, errp); > > } > > Yes, an empty list needs to be visited just like a non-empty list. > > Patch looks good. >
