From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47182) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHelH-00010G-9o for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bHelD-0000vD-JJ for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56722) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHelD-0000v9-DT for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:07 -0400 From: Thomas Huth Date: Tue, 28 Jun 2016 00:12:03 +0200 Message-Id: <1467065523-13881-1-git-send-email-thuth@redhat.com> Subject: [Qemu-devel] [PATCH] virtio: Tell the user what went wrong when event_notifier_init failed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , qemu-devel@nongnu.org Cc: Cornelia Huck , armbru@redhat.com event_notifier_init() can fail in real life, for example when there are not enough open file handles available (EMFILE) when using a lot of devices. So instead of leaving the average user with a cryptic error number only, print out a proper error message with strerror() instead, so that the user has a better way to figure out what is going on and that using "ulimit -n" might help here for example. Signed-off-by: Thomas Huth --- hw/virtio/virtio-bus.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c index 1313760..08e38fb 100644 --- a/hw/virtio/virtio-bus.c +++ b/hw/virtio/virtio-bus.c @@ -164,7 +164,8 @@ static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus, if (assign) { r = event_notifier_init(notifier, 1); if (r < 0) { - error_report("%s: unable to init event notifier: %d", __func__, r); + error_report("%s: unable to init event notifier: %s (%d)", + __func__, strerror(-r), r); return r; } virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler); -- 1.8.3.1