From: Zhao Liu <[email protected]>
As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():
* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
* error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.
ERRP_GUARD() could avoid the case when @errp is the pointer of
error_fatal, the user can't see this additional information, because
exit() happens in error_setg earlier than information is added [1].
The xen_console_connect() passes @errp to error_prepend() without
ERRP_GUARD().
There're 2 places will call xen_console_connect():
- xen_console_realize(): the @errp is from DeviceClass.realize()'s
parameter.
- xen_console_frontend_changed(): the @errp points its caller's
@local_err.
To avoid the issue like [1] said, add missing ERRP_GUARD() at the
beginning of xen_console_connect().
[1]: Issue description in the commit message of commit ae7c80a7bd73
("error: New macro ERRP_GUARD()").
Cc: Stefano Stabellini <[email protected]>
Cc: Anthony Perard <[email protected]>
Cc: Paul Durrant <[email protected]>
Cc: "Marc-André Lureau" <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Signed-off-by: Zhao Liu <[email protected]>
Acked-by: Anthony PERARD <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
---
hw/char/xen_console.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index 5cbee2f184..683c92aca1 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -206,6 +206,7 @@ static bool con_event(void *_xendev)
static bool xen_console_connect(XenDevice *xendev, Error **errp)
{
+ ERRP_GUARD();
XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
unsigned int port, limit;
--
2.41.0
