Hello Eric Dumazet,
The patch 28f922213886: "net/smc: fix ref_tracker issue in
smc_pnet_add()" from Feb 5, 2022, leads to the following Smatch
static checker warning:
net/smc/smc_pnet.c:384 smc_pnet_add_eth()
warn: sleeping in atomic context
net/smc/smc_pnet.c
342 static int smc_pnet_add_eth(struct smc_pnettable *pnettable, struct net *net,
343 char *eth_name, char *pnet_name)
344 {
345 struct smc_pnetentry *tmp_pe, *new_pe;
346 struct net_device *ndev, *base_ndev;
347 u8 ndev_pnetid[SMC_MAX_PNETID_LEN];
348 bool new_netdev;
349 int rc;
350
351 /* check if (base) netdev already has a pnetid. If there is one, we do
352 * not want to add a pnet table entry
353 */
354 rc = -EEXIST;
355 ndev = dev_get_by_name(net, eth_name); /* dev_hold() */
356 if (ndev) {
357 base_ndev = pnet_find_base_ndev(ndev);
358 if (!smc_pnetid_by_dev_port(base_ndev->dev.parent,
359 base_ndev->dev_port, ndev_pnetid))
360 goto out_put;
361 }
362
363 /* add a new netdev entry to the pnet table if there isn't one */
364 rc = -ENOMEM;
365 new_pe = kzalloc(sizeof(*new_pe), GFP_KERNEL);
366 if (!new_pe)
367 goto out_put;
368 new_pe->type = SMC_PNET_ETH;
369 memcpy(new_pe->pnet_name, pnet_name, SMC_MAX_PNETID_LEN);
370 strncpy(new_pe->eth_name, eth_name, IFNAMSIZ);
371 rc = -EEXIST;
372 new_netdev = true;
373 write_lock(&pnettable->lock);
374 list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
375 if (tmp_pe->type == SMC_PNET_ETH &&
376 !strncmp(tmp_pe->eth_name, eth_name, IFNAMSIZ)) {
377 new_netdev = false;
378 break;
379 }
380 }
381 if (new_netdev) {
382 if (ndev) {
383 new_pe->ndev = ndev;
--> 384 netdev_tracker_alloc(ndev, &new_pe->dev_tracker,
385 GFP_KERNEL);
We can't do a GFP_KERNEL allocation here
386 }
387 list_add_tail(&new_pe->list, &pnettable->pnetlist);
388 write_unlock(&pnettable->lock);
because we're holding this write lock
389 } else {
390 write_unlock(&pnettable->lock);
391 kfree(new_pe);
392 goto out_put;
393 }
394 if (ndev)
395 pr_warn_ratelimited("smc: net device %s "
396 "applied user defined pnetid %.16s\n",
397 new_pe->eth_name, new_pe->pnet_name);
398 return 0;
399
400 out_put:
401 dev_put(ndev);
402 return rc;
403 }
regards,
dan carpenter
