Re: [PATCH 2/2] mac80211: Free mpath object when rhashtable insertion fails

Dan Carpenter
2019-02-14T05:53:01Z

Hi Herbert,

url: https://github.com/0day-ci/linux/commits/Herbert-Xu/mac80211-Fix-incorrect-usage-of-rhashtable-walk-API/20190213-181325
base: https://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next.git master

smatch warnings:
net/mac80211/mesh_pathtbl.c:439 mesh_path_add() warn: passing zero to 'ERR_PTR'

# https://github.com/0day-ci/linux/commit/a0886e834aacf883ceaf0c34c842c4cdb4d318fd
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout a0886e834aacf883ceaf0c34c842c4cdb4d318fd
vim +/ERR_PTR +439 net/mac80211/mesh_pathtbl.c

b15dc38b9 Bob Copeland 2016-02-28 390
eb2b9311f Luis Carlos Cobo 2008-02-23 391 /**
eb2b9311f Luis Carlos Cobo 2008-02-23 392 * mesh_path_add - allocate and add a new path to the mesh path table
bf7cd94dc Johannes Berg 2013-02-15 393 * @dst: destination address of the path (ETH_ALEN length)
f698d856f Jasper Bryant-Greene 2008-08-03 394 * @sdata: local subif
eb2b9311f Luis Carlos Cobo 2008-02-23 395 *
af901ca18 André Goddard Rosa 2009-11-14 396 * Returns: 0 on success
eb2b9311f Luis Carlos Cobo 2008-02-23 397 *
eb2b9311f Luis Carlos Cobo 2008-02-23 398 * State: the initial state of the new path is set to 0
eb2b9311f Luis Carlos Cobo 2008-02-23 399 */
ae76eef02 Bob Copeland 2013-03-29 400 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
ae76eef02 Bob Copeland 2013-03-29 401 const u8 *dst)
eb2b9311f Luis Carlos Cobo 2008-02-23 402 {
349eb8cf4 Johannes Berg 2011-05-14 403 struct mesh_table *tbl;
eb2b9311f Luis Carlos Cobo 2008-02-23 404 struct mesh_path *mpath, *new_mpath;
60854fd94 Bob Copeland 2016-03-02 405 int ret;
eb2b9311f Luis Carlos Cobo 2008-02-23 406
b203ca391 Joe Perches 2012-05-08 407 if (ether_addr_equal(dst, sdata->vif.addr))
eb2b9311f Luis Carlos Cobo 2008-02-23 408 /* never add ourselves as neighbours */
ae76eef02 Bob Copeland 2013-03-29 409 return ERR_PTR(-ENOTSUPP);
eb2b9311f Luis Carlos Cobo 2008-02-23 410
eb2b9311f Luis Carlos Cobo 2008-02-23 411 if (is_multicast_ether_addr(dst))
ae76eef02 Bob Copeland 2013-03-29 412 return ERR_PTR(-ENOTSUPP);
eb2b9311f Luis Carlos Cobo 2008-02-23 413
472dbc45d Johannes Berg 2008-09-11 414 if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
ae76eef02 Bob Copeland 2013-03-29 415 return ERR_PTR(-ENOSPC);
ae76eef02 Bob Copeland 2013-03-29 416
b15dc38b9 Bob Copeland 2016-02-28 417 new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
402d7752e Pavel Emelyanov 2008-05-06 418 if (!new_mpath)
60854fd94 Bob Copeland 2016-03-02 419 return ERR_PTR(-ENOMEM);
402d7752e Pavel Emelyanov 2008-05-06 420
60854fd94 Bob Copeland 2016-03-02 421 tbl = sdata->u.mesh.mesh_paths;
60854fd94 Bob Copeland 2016-03-02 422 do {
60854fd94 Bob Copeland 2016-03-02 423 ret = rhashtable_lookup_insert_fast(&tbl->rhead,
60854fd94 Bob Copeland 2016-03-02 424 &new_mpath->rhash,
60854fd94 Bob Copeland 2016-03-02 425 mesh_rht_params);
f84e71a94 Pavel Emelyanov 2008-05-06 426
60854fd94 Bob Copeland 2016-03-02 427 if (ret == -EEXIST)
60854fd94 Bob Copeland 2016-03-02 428 mpath = rhashtable_lookup_fast(&tbl->rhead,
60854fd94 Bob Copeland 2016-03-02 429 dst,
60854fd94 Bob Copeland 2016-03-02 430 mesh_rht_params);
05b0152f1 Herbert Xu 2019-02-13 431 else if (!ret)
05b0152f1 Herbert Xu 2019-02-13 432 hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
60854fd94 Bob Copeland 2016-03-02 433 } while (unlikely(ret == -EEXIST && !mpath));
f5ea9120b Johannes Berg 2009-08-07 434
a0886e834 Herbert Xu 2019-02-13 435 if (ret)
a0886e834 Herbert Xu 2019-02-13 436 kfree(new_mpath);
a0886e834 Herbert Xu 2019-02-13 437
a0886e834 Herbert Xu 2019-02-13 438 if (ret != -EEXIST)
60854fd94 Bob Copeland 2016-03-02 @439 return ERR_PTR(ret);

if (ret && ret != -EEXIST) ?

ae76eef02 Bob Copeland 2013-03-29 440
60854fd94 Bob Copeland 2016-03-02 441 /* At this point either new_mpath was added, or we found a
60854fd94 Bob Copeland 2016-03-02 442 * matching entry already in the table; in the latter case
60854fd94 Bob Copeland 2016-03-02 443 * free the unnecessary new entry.
60854fd94 Bob Copeland 2016-03-02 444 */
a0886e834 Herbert Xu 2019-02-13 445 if (ret == -EEXIST)
60854fd94 Bob Copeland 2016-03-02 446 new_mpath = mpath;
60854fd94 Bob Copeland 2016-03-02 447 sdata->u.mesh.mesh_paths_generation++;
60854fd94 Bob Copeland 2016-03-02 448 return new_mpath;
18889231e Javier Cardona 2009-08-10 449 }
eb2b9311f Luis Carlos Cobo 2008-02-23 450

:::::: The code at line 439 was first introduced by commit
:::::: 60854fd94573f0d3b80b55b40cf0140a0430f3ab mac80211: mesh: convert path table to rhashtable

:::::: TO: Bob Copeland <me@bobcopeland.com>
:::::: CC: Johannes Berg <johannes.berg@intel.com>

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