From 5cf8f51c033d0b2817f791757edcf7d6da787526 Mon Sep 17 00:00:00 2001 From: Zhao Liu Date: Mon, 11 Mar 2024 11:38:14 +0800 Subject: [PATCH] hw/vfio/iommufd: Fix missing ERRP_GUARD() for error_prepend() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 &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(), and there are too many possible callers to check the impact of this defect; it may or may not be harmless. Thus it is necessary to protect @errp 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 Cc: Cédric Le Goater Signed-off-by: Zhao Liu Reviewed-by: Cédric Le Goater Message-ID: <20240311033822.3142585-22-zhao1.liu@linux.intel.com> Signed-off-by: Thomas Huth --- 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;