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hw/vfio/helpers: Fix missing ERRP_GUARD() for error_prepend()

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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].

In hw/vfio/helpers.c, there are 3 functions passing @errp to
error_prepend() without ERRP_GUARD():
 - vfio_set_irq_signaling()
 - vfio_device_get_name()
 - vfio_device_set_fd()

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 their
@errp 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.williamson@redhat.com>
Cc: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Message-ID: <20240311033822.3142585-21-zhao1.liu@linux.intel.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Zhao Liu 2024-03-11 11:38:13 +08:00 committed by Thomas Huth
parent 93a518ba56
commit 89a8a2e9c4
1 changed files with 3 additions and 0 deletions
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3
hw/vfio/helpers.c
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@ -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 vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
int action, int fd, Error **errp) int action, int fd, Error **errp)
{ {
ERRP_GUARD();
struct vfio_irq_set *irq_set; struct vfio_irq_set *irq_set;
int argsz, ret = 0; int argsz, ret = 0;
const char *name; 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) int vfio_device_get_name(VFIODevice *vbasedev, Error **errp)
{ {
ERRP_GUARD();
struct stat st; struct stat st;
if (vbasedev->fd < 0) { 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) void vfio_device_set_fd(VFIODevice *vbasedev, const char *str, Error **errp)
{ {
ERRP_GUARD();
int fd = monitor_fd_param(monitor_cur(), str, errp); int fd = monitor_fd_param(monitor_cur(), str, errp);
if (fd < 0) { if (fd < 0) {