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hw/display/macfb: Fix missing ERRP_GUARD() in macfb_nubus_realize()

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As the comment in qapi/error, dereferencing @errp requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
* - It must not be dereferenced, because it may be null.
...
* 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.
*
* Using it when it's not needed is safe, but please avoid cluttering
* the source with useless code.

But in macfb_nubus_realize(), @errp is dereferenced without
ERRP_GUARD():

ndc->parent_realize(dev, errp);
if (*errp) {
    return;
}

Here we check *errp, because the ndc->parent_realize(), as a
DeviceClass.realize() callback, returns void. And since
macfb_nubus_realize(), also as a DeviceClass.realize(), doesn't get the
NULL @errp parameter, it hasn't triggered the bug that dereferencing the
NULL @errp.

To follow the requirement of @errp, add missing ERRP_GUARD() in
macfb_nubus_realize().

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20240223085653.1255438-3-zhao1.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Zhao Liu 2024-02-23 16:56:48 +08:00 committed by Michael S. Tsirkin
parent 2a0e0a3500
commit 5aa4a6417b
1 changed files with 1 additions and 0 deletions
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1
hw/display/macfb.c
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@ -714,6 +714,7 @@ static void macfb_nubus_set_irq(void *opaque, int n, int level)
static void macfb_nubus_realize(DeviceState *dev, Error **errp)
{
ERRP_GUARD();
NubusDevice *nd = NUBUS_DEVICE(dev);
MacfbNubusState *s = NUBUS_MACFB(dev);
MacfbNubusDeviceClass *ndc = NUBUS_MACFB_GET_CLASS(dev);