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].
In hw/vfio/helpers.c, there're 3 functions passing @errp to
error_prepend() without ERRP_GUARD():
- vfio_set_irq_signaling()
- vfio_device_get_name()
- vfio_device_set_fd()
As the widely used helpers, their @errp parameters are so widely sourced
that it is necessary to protect them with ERRP_GUARD().
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>
Reviewed-by: Cédric Le Goater <c...@redhat.com>
Thanks,
C.
---
hw/vfio/helpers.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index 678987080228..47b4096c05ee 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -110,6 +110,7 @@ static const char *index_to_str(VFIODevice *vbasedev, int
index)
int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
int action, int fd, Error **errp)
{
+ ERRP_GUARD();
struct vfio_irq_set *irq_set;
int argsz, ret = 0;
const char *name;
@@ -613,6 +614,7 @@ bool vfio_has_region_cap(VFIODevice *vbasedev, int region,
uint16_t cap_type)
int vfio_device_get_name(VFIODevice *vbasedev, Error **errp)
{
+ ERRP_GUARD();
struct stat st;
if (vbasedev->fd < 0) {
@@ -644,6 +646,7 @@ int vfio_device_get_name(VFIODevice *vbasedev, Error **errp)
void vfio_device_set_fd(VFIODevice *vbasedev, const char *str, Error **errp)
{
+ ERRP_GUARD();
int fd = monitor_fd_param(monitor_cur(), str, errp);
if (fd < 0) {
