On 2/29/24 15:39, Zhao Liu wrote:
From: Zhao Liu <zhao1....@intel.com>
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 iommufd_cdev_getfd() passes @errp to error_prepend(). Its @errp is
from vfio_attach_device(), which @errp parameter is so widely sourced
that it is necessary to protect it with ERRP_GUARD().
To avoid the issue like [1] said, add missing ERRP_GUARD() at the
beginning of this function.
[1]: Issue description in the commit message of commit ae7c80a7bd73
("error: New macro ERRP_GUARD()").
Cc: Alex Williamson <alex.william...@redhat.com>
Cc: "Cédric Le Goater" <c...@redhat.com>
Signed-off-by: Zhao Liu <zhao1....@intel.com>
Reviewed-by: Cédric Le Goater <c...@redhat.com>
Thanks,
C.
---
hw/vfio/iommufd.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 9bfddc136089..7baf49e6ee9e 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;
