util/event_notifier: fix error handling for event_notifier_init callers

Check return value of event_notifier_init() and return early on
failure instead of continuing with invalid state.
- Use ret < 0 to handle negative return value.
- No functional changes.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/413
Signed-off-by: Trieu Huynh <vikingtc4@gmail.com>
Acked-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> # for the Hyper-V part
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-ID: <20260318141415.8538-4-vikingtc4@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/hyperv/hyperv.c

@@ -439,7 +439,7 @@ HvSintRoute *hyperv_sint_route_new(uint32_t vp_index, uint32_t sint,
         sint_route->staged_msg->cb_data = cb_data;
 
         r = event_notifier_init(ack_notifier, false);
-        if (r) {
+        if (r < 0) {
             goto cleanup_err_sint;
         }
         event_notifier_set_handler(ack_notifier, sint_ack_handler);
@@ -453,7 +453,7 @@ HvSintRoute *hyperv_sint_route_new(uint32_t vp_index, uint32_t sint,
 
     /* We need to setup a GSI for this SintRoute */
     r = event_notifier_init(&sint_route->sint_set_notifier, false);
-    if (r) {
+    if (r < 0) {
         goto cleanup_err_sint;
     }
 

hw/hyperv/vmbus.c

@@ -1432,7 +1432,7 @@ static void open_channel(VMBusChannel *chan)
         goto put_gpadl;
     }
 
-    if (event_notifier_init(&chan->notifier, 0)) {
+    if (event_notifier_init(&chan->notifier, 0) < 0) {
         goto put_gpadl;
     }
 
@@ -2450,7 +2450,7 @@ static void vmbus_realize(BusState *bus, Error **errp)
     }
 
     ret = event_notifier_init(&vmbus->notifier, 0);
-    if (ret != 0) {
+    if (ret < 0) {
         error_setg(errp, "event notifier failed to init with %d", ret);
         goto remove_msg_handler;
     }

hw/remote/proxy.c

@@ -52,9 +52,20 @@ static void setup_irqfd(PCIProxyDev *dev)
     PCIDevice *pci_dev = PCI_DEVICE(dev);
     MPQemuMsg msg;
     Error *local_err = NULL;
+    int ret = 0;
 
-    event_notifier_init(&dev->intr, 0);
-    event_notifier_init(&dev->resample, 0);
+    ret = event_notifier_init(&dev->intr, 0);
+    if (ret < 0) {
+        error_report("Failed to init intr notifier: %s", strerror(-ret));
+        return;
+    }
+
+    ret = event_notifier_init(&dev->resample, 0);
+    if (ret < 0) {
+        error_report("Failed to init resample notifier: %s", strerror(-ret));
+        event_notifier_cleanup(&dev->intr);
+        return;
+    }
 
     memset(&msg, 0, sizeof(MPQemuMsg));
     msg.cmd = MPQEMU_CMD_SET_IRQFD;

hw/vfio/ap.c

@@ -180,7 +180,7 @@ static bool vfio_ap_register_irq_notifier(VFIOAPDevice *vapdev,
         return false;
     }
 
-    if (event_notifier_init(notifier, 0)) {
+    if (event_notifier_init(notifier, 0) < 0) {
         error_setg_errno(errp, errno,
                          "vfio: Unable to init event notifier for irq (%d)",
                          irq);

hw/vfio/ccw.c

@@ -418,7 +418,7 @@ static bool vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
         return false;
     }
 
-    if (event_notifier_init(notifier, 0)) {
+    if (event_notifier_init(notifier, 0) < 0) {
         error_setg_errno(errp, errno,
                          "vfio: Unable to init event notifier for irq (%d)",
                          irq);

hw/vfio/pci-quirks.c

@@ -318,7 +318,7 @@ static VFIOIOEventFD *vfio_ioeventfd_init(VFIOPCIDevice *vdev,
 
     ioeventfd = g_malloc0(sizeof(*ioeventfd));
 
-    if (event_notifier_init(&ioeventfd->e, 0)) {
+    if (event_notifier_init(&ioeventfd->e, 0) < 0) {
         g_free(ioeventfd);
         return NULL;
     }

hw/vfio/pci.c

@@ -70,7 +70,7 @@ static bool vfio_notifier_init(VFIOPCIDevice *vdev, EventNotifier *e,
     }
 
     ret = event_notifier_init(e, 0);
-    if (ret) {
+    if (ret < 0) {
         error_setg_errno(errp, -ret, "vfio_notifier_init %s failed", name);
         return false;
     }

hw/virtio/vhost-vdpa.c

@@ -1075,13 +1075,13 @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
     int r;
 
     r = event_notifier_init(&svq->hdev_kick, 0);
-    if (r != 0) {
+    if (r < 0) {
         error_setg_errno(errp, -r, "Couldn't create kick event notifier");
         goto err_init_hdev_kick;
     }
 
     r = event_notifier_init(&svq->hdev_call, 0);
-    if (r != 0) {
+    if (r < 0) {
         error_setg_errno(errp, -r, "Couldn't create call event notifier");
         goto err_init_hdev_call;
     }