Hello stephen hemminger,
The patch 9749fed5d43d: "netvsc: use ERR_PTR to avoid dereference
issues" from Jul 19, 2017, leads to the following static checker
warning:
drivers/net/hyperv/rndis_filter.c:1344 rndis_filter_device_add()
warn: passing zero to 'ERR_PTR'
drivers/net/hyperv/rndis_filter.c
1300 ret = rndis_filter_query_device(rndis_device, net_device,
1301 OID_GEN_RECEIVE_SCALE_CAPABILITIES,
1302 &rsscap, &rsscap_size);
1303 if (ret || rsscap.num_recv_que < 2)
^^^^^^^^^^^^^^^^^^^^^^^
I think this used to be a success path, but now it leads to a NULL
dereference in the caller. I guess we should set "ret = -ENOMEM;" here?
1304 goto out;
1305
1306 /* This guarantees that num_possible_rss_qs <= num_online_cpus */
1307 num_possible_rss_qs = min_t(u32, num_online_cpus(),
1308 rsscap.num_recv_que);
1309
1310 net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, num_possible_rss_qs);
1311
1312 /* We will use the given number of channels if available. */
1313 net_device->num_chn = min(net_device->max_chn, device_info->num_chn);
1314
1315 for (i = 0; i < ITAB_NUM; i++)
1316 rndis_device->rx_table[i] = ethtool_rxfh_indir_default(
1317 i, net_device->num_chn);
1318
1319 atomic_set(&net_device->open_chn, 1);
1320 vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
1321
1322 for (i = 1; i < net_device->num_chn; i++) {
1323 ret = netvsc_alloc_recv_comp_ring(net_device, i);
1324 if (ret) {
1325 while (--i != 0)
1326 vfree(net_device->chan_table[i].mrc.slots);
1327 goto out;
1328 }
1329 }
1330
1331 for (i = 1; i < net_device->num_chn; i++)
1332 netif_napi_add(net, &net_device->chan_table[i].napi,
1333 netvsc_poll, NAPI_POLL_WEIGHT);
1334
1335 return net_device;
1336
1337 out:
1338 /* setting up multiple channels failed */
1339 net_device->max_chn = 1;
1340 net_device->num_chn = 1;
1341
1342 err_dev_remv:
1343 rndis_filter_device_remove(dev, net_device);
1344 return ERR_PTR(ret);
regards,
dan carpenter
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