The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

machine_parse_property_opt() is wrong that way: it passes @errp to
keyval_parse() without checking for failure, then passes it to
keyval_merge().  Harmless, since the only caller passes &error_fatal.

Clean up: drop the parameter, and use &error_fatal directly.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210720125408.387910-16-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
[Rebased, conflict with commit a3c2f128306 resolved]
---
 softmmu/vl.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 6227f8f10e..bdeb17809d 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1550,20 +1550,17 @@ machine_merge_property(const char *propname, QDict *prop, Error **errp)
 
 static void
 machine_parse_property_opt(QemuOptsList *opts_list, const char *propname,
-                           const char *arg, Error **errp)
+                           const char *arg)
 {
     QDict *prop = NULL;
     bool help = false;
 
-    prop = keyval_parse(arg, opts_list->implied_opt_name, &help, errp);
+    prop = keyval_parse(arg, opts_list->implied_opt_name, &help, &error_fatal);
     if (help) {
         qemu_opts_print_help(opts_list, true);
         exit(0);
     }
-    if (!prop) {
-        return;
-    }
-    machine_merge_property(propname, prop, errp);
+    machine_merge_property(propname, prop, &error_fatal);
     qobject_unref(prop);
 }
 
@@ -3343,7 +3340,8 @@ void qemu_init(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_smp:
-                machine_parse_property_opt(qemu_find_opts("smp-opts"), "smp", optarg, &error_fatal);
+                machine_parse_property_opt(qemu_find_opts("smp-opts"),
+                                           "smp", optarg);
                 break;
             case QEMU_OPTION_vnc:
                 vnc_parse(optarg);
-- 
2.31.1