From bd74ecd1c39ca7699819ca5cf39c07f50c5f8d5d Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 24 Mar 2021 09:41:30 +0100 Subject: qom: Fix default values in help MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Output of default values in device help is broken: $ ./qemu-system-x86_64 -S -display none -monitor stdio QEMU 5.2.50 monitor - type 'help' for more information (qemu) device_add pvpanic,help pvpanic options: events= - (default: (null)) ioport= - (default: (null)) pvpanic[0]=> The "(null)" is glibc printing a null pointer. Other systems crash instead. Having a help request crash a running VM can really spoil your day. Root cause is a botched replacement of qstring_free() by g_string_free(): to get the string back, we need to pass true to the former, but false to the latter. Fix the argument. Fixes: eab3a4678b07267c39e7290a6e9e7690b1d2a521 Reported-by: Thomas Huth Signed-off-by: Markus Armbruster Reviewed-by: Marc-André Lureau Reviewed-by: Thomas Huth Message-Id: <20210324084130.3986072-1-armbru@redhat.com> Signed-off-by: Thomas Huth --- qom/object_interfaces.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'qom') diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c index c3324b0..bd8a947 100644 --- a/qom/object_interfaces.c +++ b/qom/object_interfaces.c @@ -159,7 +159,7 @@ char *object_property_help(const char *name, const char *type, } if (defval) { g_autofree char *def_json = g_string_free(qobject_to_json(defval), - true); + false); g_string_append_printf(str, " (default: %s)", def_json); } -- cgit v1.1