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/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>
Reviewed-by: Cédric Le Goater <c...@redhat.com> Thanks, C.
