From: Zhao Liu <zhao1....@intel.com>
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 iommufd_cdev_getfd(), @errp is dereferenced without ERRP_GUARD():
if (*errp) {
error_prepend(errp, VFIO_MSG_PREFIX, path);
}
Currently, since vfio_attach_device() - the caller of
iommufd_cdev_getfd() - is always called in DeviceClass.realize() context
and doesn't get the NULL @errp parameter, iommufd_cdev_getfd()
hasn't triggered the bug that dereferencing the NULL @errp.
To follow the requirement of @errp, add missing ERRP_GUARD() in
iommufd_cdev_getfd().
Suggested-by: Markus Armbruster <arm...@redhat.com>
Signed-off-by: Zhao Liu <zhao1....@intel.com>
Reviewed-by: Markus Armbruster <arm...@redhat.com>
Message-Id: <20240223085653.1255438-7-zhao1....@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
hw/vfio/iommufd.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 9bfddc1360..7baf49e6ee 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -116,6 +116,7 @@ static void iommufd_cdev_unbind_and_disconnect(VFIODevice
*vbasedev)
static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
{
+ ERRP_GUARD();
long int ret = -ENOTTY;
char *path, *vfio_dev_path = NULL, *vfio_path = NULL;
DIR *dir = NULL;
--
MST
