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].
In hw/vfio/pci.c, there're 2 functions passing @errp to error_prepend()
without ERRP_GUARD():
- vfio_add_std_cap()
- vfio_realize()
The @errp of vfio_add_std_cap() is also from vfio_realize(). And
vfio_realize(), as a PCIDeviceClass.realize method, its @errp is from
DeviceClass.realize so that there is no guarantee that the @errp won't
point to @error_fatal.
To avoid the issue like [1] said, add missing ERRP_GUARD() at their
beginning.
[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>
---
hw/vfio/pci.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 4fa387f0430d..e70efde11913 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2136,6 +2136,7 @@ static void vfio_check_af_flr(VFIOPCIDevice *vdev,
uint8_t pos)
static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t pos, Error **errp)
{
+ ERRP_GUARD();
PCIDevice *pdev = &vdev->pdev;
uint8_t cap_id, next, size;
int ret;
@@ -2942,6 +2943,7 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice
*vdev)
static void vfio_realize(PCIDevice *pdev, Error **errp)
{
+ ERRP_GUARD();
VFIOPCIDevice *vdev = VFIO_PCI(pdev);
VFIODevice *vbasedev = &vdev->vbasedev;
char *tmp, *subsys;
--
2.34.1
