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 &error_fatal, the user can't see this additional information, because exit() happens in error_setg earlier than information is added [1]. The net_init_vhost_vdpa() passes @errp to error_prepend(), and as a member of net_client_init_fun[], it's called in net_client_init1() and gets @errp from this caller. But because netdev_init_modern() passes &error_fatal to net_client_init1(), then @errp parameter of net_init_vhost_vdpa() would point to @error_fatal. This causes the error message in error_prepend() to be lost because of the above issue. To fix this, 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: Jason Wang <jasow...@redhat.com> Signed-off-by: Zhao Liu <zhao1....@intel.com> Reviewed-by: Thomas Huth <th...@redhat.com> --- net/vhost-vdpa.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index e6bdb4562dde..d81baecbc1a3 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -1751,6 +1751,7 @@ static int vhost_vdpa_get_max_queue_pairs(int fd, uint64_t features, int net_init_vhost_vdpa(const Netdev *netdev, const char *name, NetClientState *peer, Error **errp) { + ERRP_GUARD(); const NetdevVhostVDPAOptions *opts; uint64_t features; int vdpa_device_fd; -- 2.34.1