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>
---
 softmmu/vl.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index f9ffeb8d4d..ce0ecc736b 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1535,19 +1535,19 @@ static void machine_help_func(const QDict *qdict)
 
 static void
 machine_parse_property_opt(QemuOptsList *opts_list, const char *propname,
-                           const char *arg, Error **errp)
+                           const char *arg)
 {
     QDict *opts, *prop;
     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);
         return;
     }
     opts = qdict_new();
     qdict_put(opts, propname, prop);
-    keyval_merge(machine_opts_dict, opts, errp);
+    keyval_merge(machine_opts_dict, opts, &error_fatal);
     qobject_unref(opts);
 }
 
@@ -3321,7 +3321,8 @@ 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

On 7/20/21 2:54 PM, Markus Armbruster wrote:
> 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>
> ---
>  softmmu/vl.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>