From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:54814) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1guEtz-00051e-7i for qemu-devel@nongnu.org; Thu, 14 Feb 2019 06:09:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1guEi5-0003OD-Bd for qemu-devel@nongnu.org; Thu, 14 Feb 2019 05:57:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33248) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1guEi5-0003Mi-5I for qemu-devel@nongnu.org; Thu, 14 Feb 2019 05:57:41 -0500 From: Igor Mammedov Date: Thu, 14 Feb 2019 05:57:33 -0500 Message-Id: <20190214105733.25643-1-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v2] hostmem: fix crash when querying empty host-nodes property via QMP List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: mdroth@linux.vnet.ibm.com, ehabkost@redhat.com, armbru@redhat.com 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 not set hostmem's "host-nodes" property, HostMemoryBackend::host_nodes bitmap doesn't have any bits set in it, which leads to find_first_bit() returning MAX_NODES and consequently to an early return from host_memory_backend_get_host_nodes() without calling visitor. Fix it by calling visitor even if "host-nodes" property wasn't set before exiting from property getter to return valid empty list. Signed-off-by: Igor Mammedov --- v2: * fixup commit message to put emphasis on property instead local variable host_nodes and make explanation more hopefully more clear. (Markus Armbruster ) --- backends/hostmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 87b19d2111..04baf479a1 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -88,7 +88,7 @@ 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)); @@ -106,6 +106,7 @@ 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); } -- 2.18.1